Impact resistant underbody shield materials and articles and methods of using them

ABSTRACT

Underbody shield materials that can provide an underbody shield with high impact resistance are described. In some configurations, an underbody shield composition comprises a porous core layer comprising a plurality of reinforcing fibers, a lofting agent and a thermoplastic material. In some instances, the underbody shield composition may also comprise a film such that an underbody shield produced from the composition can withstand at least 50 individual impacts as tested using a SAE J400 protocol.

PRIORITY APPLICATION

This application is related to and claims the benefit of and priority toU.S. Provisional Application No. 62/175,004 filed on Jun. 12, 2015, theentire disclosure of which is hereby incorporated herein by referencefor all purposes.

TECHNOLOGICAL FIELD

This application is related to underbody shield materials that provideimpact resistance. More particularly, certain embodiments describedherein are directed to underbody shield materials that can be used in animpact resistant underbody shield that comprises a core layer and a filmtogether effective to provide the impact resistance.

BACKGROUND

Articles for automotive and construction materials applicationstypically are designed to meet a number of competing and stringentperformance specifications.

SUMMARY

Certain configurations are described herein that are directed tomaterials which can be used in multi-layer assemblies, and componentsthereof, that provide impact resistance as tested according to SAEStandard J400 dated Oct. 23, 2012 (referred to hereafter as “agravelometer test”), which is similar to ASTM D3170-14 dated Jul. 1,2014. For example, the materials can be used to produce a compositearticle that can withstand 50 or more individual impacts, e.g., 100 ormore individual impacts, as provided under the gravelometer testconditions, without any substantial damage or effects to the article.

In one aspect, an underbody shield composition comprising athermoplastic core layer comprising a web of open celled structuresdefined by random crossing over of reinforcing fibers held together by athermoplastic polymer, the thermoplastic core layer further comprising alofting agent effective to increase a thickness of the core layer uponexposure to heat to provide a post lofted core layer, and a filmdisposed on a first surface of the core layer, in which the post loftedcore layer and film together provide an underbody shield article thatcan withstand at least 50 individual impacts according to a SAE J400protocol without damage to the film is provided.

In certain embodiments, the film is a homopolymer or copolymer film,e.g., an impact modified homopolymer or copolymer film. In otherembodiments, the homopolymer is a polyolefin. In some instances, thethermoplastic polymer is present at 50 weight percent or more in thecore layer. In other embodiments, the film is at least 10 mils thick. Insome examples, the lofting agent is present at 4 percent by weight ormore in the core layer. In other examples, the reinforcing fibers areselected from the group consisting of glass fibers, carbon fibers,graphite fibers, synthetic organic fibers, inorganic fibers, naturalfibers, mineral fibers, metal fibers, metalized inorganic fibers,metalized synthetic fibers, ceramic fibers, and combinations thereof. Incertain embodiments, the thermoplastic polymer is a polymer resin thatis selected from the group consisting of a polyolefin resin, athermoplastic polyolefin blend resin, a polyvinyl polymer resin, abutadiene polymer resin, an acrylic polymer resin, a polyamide resin, apolyester resin, a polycarbonate resin, a polyestercarbonate resin, apolystyrene resin, an acrylonitrylstyrene polymer resin, anacrylonitrile-butylacrylate-styrene polymer resin, a polyether imideresin, a polyphenylene ether resin, a polyphenylene oxide resin, apolyphenylenesulphide resin, a polyether resin, a polyetherketone resin,a polyacetal resin, a polyurethane resin, a polybenzimidazole resin, andcopolymers and mixtures thereof. In some examples, the thermoplasticcore layer comprises polypropylene, glass fibers and microsphere loftingagents, and in which the film is a polypropylene homopolymer film. Inother examples, the film is directly disposed on the first surface ofthe core layer without any intervening layer or material. In someinstances, the composition may comprise a scrim disposed on a secondsurface of the core layer opposite the first surface of the core layer.In certain examples, the scrim comprises glass fibers, aramid fibers,graphite fibers, carbon fibers, inorganic mineral fibers, metal fibers,metalized synthetic fibers, and metalized inorganic fibers. In otherexamples, the composition comprises an additional skin layer disposed onthe scrim. In some embodiments, the thermoplastic core layer comprisespolypropylene, glass fibers and microsphere lofting agents, in which thefilm is a polypropylene homopolymer film and the scrim is polyesternonwoven scrim. In certain examples, the film is directly disposed onthe first surface of the core layer without any intervening layer ormaterial and the scrim is directly disposed on the second surface of thecore layer without any intervening layer or material. In some instances,the scrim is disposed as one or more strips on the second surface of thecore layer. In other embodiments, the composition further comprises anadditional core layer coupled to the core layer, the additional corelayer comprising a web of open celled structures defined by randomcrossing over of reinforcing fibers held together by a thermoplasticpolymer. In some examples, the additional core layer further comprises alofting agent effective to increase a thickness of the additional corelayer. In other embodiments, the additional core layer comprises a lowerweight percentage of thermoplastic material than an amount ofthermoplastic material present in the core layer. In certain instances,the film is configured to withstand more impacts as a thickness of thecore layer is decreased.

In another aspect, an underbody shield composition comprising athermoplastic core layer comprising a web of open celled structuresdefined by random crossing over of reinforcing fibers held together by athermoplastic polymer, the thermoplastic core layer further comprising alofting agent effective to increase a thickness of the core layer uponexposure to heat to provide a post lofted core layer, a homopolymerpolyolefin film or a copolymer polyolefin film disposed on a firstsurface of the core layer, a scrim disposed on a second surface of thecore layer, in which the post lofted core layer, film and scrim togetherprovide an underbody shield article that can withstand at least 50individual impacts according to a SAE J400 protocol without damage tothe film is provided.

In certain instances, the composition comprises a decorative layerdisposed on the scrim. In other instances, the thermoplastic core layercomprises a void content of greater than 5% and up to about 95%. In someembodiments, the thermoplastic polymer is present at 50 weight percentor more in the core layer. In other embodiments, the film is at least 10mils thick. In certain examples, the lofting agent is present at 4percent by weight or more in the core layer. In other examples, thereinforcing fibers are selected from the group consisting of glassfibers, carbon fibers, graphite fibers, synthetic organic fibers,inorganic fibers, natural fibers, mineral fibers, metal fibers,metalized inorganic fibers, metalized synthetic fibers, ceramic fibers,and combinations thereof. In some embodiments, the thermoplastic polymeris a polymer resin that is selected from the group consisting of apolyolefin resin, a thermoplastic polyolefin blend resin, a polyvinylpolymer resin, a butadiene polymer resin, an acrylic polymer resin, apolyamide resin, a polyester resin, a polycarbonate resin, apolyestercarbonate resin, a polystyrene resin, an acrylonitrylstyrenepolymer resin, an acrylonitrile-butylacrylate-styrene polymer resin, apolyether imide resin, a polyphenylene ether resin, a polyphenyleneoxide resin, a polyphenylenesulphide resin, a polyether resin, apolyetherketone resin, a polyacetal resin, a polyurethane resin, apolybenzimidazole resin, and copolymers and mixtures thereof. In otherembodiments, the thermoplastic core layer comprises polypropylene, glassfibers and microsphere lofting agents, and in which the film is apolypropylene homopolymer film. In some examples, the film is directlydisposed on the first surface of the core layer without any interveninglayer or material.

In an additional aspect, a prepreg comprises a first layer comprising athermoplastic polymer, reinforcing fibers and a lofting agent, the firstlayer effective to form a layer comprising a web of open cell structuresupon curing of the first layer, wherein the web open celled structuresis defined by random crossing over of the reinforcing fibers heldtogether by the thermoplastic polymer with the lofting agent trapped inthe open cell structures of the web, wherein the lofting agent iseffective to increase a thickness of the first layer after exposure toheat to provide a post-lofted first layer, and a film disposed on afirst surface of the first layer, in which the post lofted first layerand film together can withstand at least 50 individual impacts accordingto a SAE J400 protocol without damage to the film.

In some examples, the film is a homopolymer film, e.g., an impactmodified homopolymer film. In other examples, the homopolymer is apolyolefin. In some embodiments, the thermoplastic polymer is present at50 weight percent or more in the first layer. In other embodiments, thefilm is at least 10 mils thick. In some examples, the lofting agent ispresent at 4 percent by weight or more in the first layer. In otherexamples, the reinforcing fibers are selected from the group consistingof glass fibers, carbon fibers, graphite fibers, synthetic organicfibers, inorganic fibers, natural fibers, mineral fibers, metal fibers,metalized inorganic fibers, metalized synthetic fibers, ceramic fibers,and combinations thereof. In some embodiments, the thermoplastic polymeris a polymer resin that is selected from the group consisting of apolyolefin resin, a thermoplastic polyolefin blend resin, a polyvinylpolymer resin, a butadiene polymer resin, an acrylic polymer resin, apolyamide resin, a polyester resin, a polycarbonate resin, apolyestercarbonate resin, a polystyrene resin, an acrylonitrylstyrenepolymer resin, an acrylonitrile-butylacrylate-styrene polymer resin, apolyether imide resin, a polyphenylene ether resin, a polyphenyleneoxide resin, a polyphenylenesulphide resin, a polyether resin, apolyetherketone resin, a polyacetal resin, a polyurethane resin, apolybenzimidazole resin, and copolymers and mixtures thereof. In otherembodiments, the first layer comprises polypropylene, glass fibers andmicrosphere lofting agents, and in which the film is a polypropylenehomopolymer film. In further examples, the film is directly disposed onthe first surface of the first layer without any intervening layer ormaterial. In some instances, the prepreg comprises a scrim disposed on asecond surface of the first layer opposite the first surface of thefirst layer. In certain examples, the scrim comprises glass fibers,aramid fibers, graphite fibers, carbon fibers, inorganic mineral fibers,metal fibers, metalized synthetic fibers, and metalized inorganicfibers. In other examples, the prepreg comprises an additional skinlayer disposed on the scrim. In some embodiments, the first layercomprises polypropylene, glass fibers and microsphere lofting agents, inwhich the film is a polypropylene homopolymer film and the scrim ispolyester non-woven scrim. In other examples, the film is directlydisposed on the first surface of the first layer without any interveninglayer or material and the scrim is directly disposed on the secondsurface of the first layer without any intervening layer or material. Insome examples, the scrim is disposed as one or more strips on the secondsurface of the first layer. In certain instances, the prepreg comprisesan additional layer coupled to the first layer, the additional layercomprising a web of open celled structures defined by random crossingover of reinforcing fibers held together by a thermoplastic polymer. Inother embodiments, the additional layer further comprises a loftingagent effective to increase a thickness of the additional layer. In someexamples, the additional layer comprises a lower weight percentage ofthermoplastic material than an amount of thermoplastic material presentin the first layer. In some examples, the film is configured towithstand more impacts as a thickness of the first layer is decreased.

In another aspect, a underbody shield comprises a thermoplastic corelayer comprising a web of open celled structures defined by randomcrossing over of reinforcing fibers held together by a thermoplasticpolymer, the thermoplastic core layer further comprising a lofting agenteffective to increase a thickness of the core layer upon exposure toheat to provide a post lofted core layer, a film disposed on a firstsurface of the core layer, in which the post lofted core layer and filmtogether provide the underbody shield that can withstand at least 50individual impacts according to a SAE J400 protocol without damage tothe film, in which the underbody shield comprises one or more attachmentareas to couple to an underside of a vehicle.

In certain examples, the underbody shield is shaped to reduce acoefficient of drag on a vehicle when the underbody shield is coupled tothe vehicle. In other examples, the film is a homopolymer polyolefinfilm. In some examples, the thermoplastic polymer is present at 50weight percent or more in the core layer. In certain examples, the filmis at least 10 mils thick. In other examples, the lofting agent ispresent at 4 percent by weight or more in the core layer. In someembodiments, the thermoplastic core layer comprises polypropylene, glassfibers and microsphere lofting agents, and in which the film is apolypropylene homopolymer film. In other embodiments, the film isdirectly disposed on the first surface of the core layer without anyintervening layer or material. In certain examples, the underbody shieldfurther comprises a scrim disposed on a second surface of the core layeropposite the first surface of the core layer. In other examples, thethermoplastic core layer comprises polypropylene, glass fibers andmicrosphere lofting agents, in which the film is a polypropylenehomopolymer film and the scrim is polyester non-woven scrim. In someembodiments, a method of forming a composite prepreg comprises combininga thermoplastic polymer, reinforcing fibers and a lofting agent in anaqueous solution, mixing the aqueous solution comprising thethermoplastic polymer, reinforcing fibers and lofting agent to dispersethe reinforcing fibers and the lofting agent in the thermoplasticpolymer to provide an aqueous foam dispersion, disposing the aqueousfoam dispersion onto a forming element, removing liquid from thedisposed aqueous foam to provide a web comprising the thermoplasticpolymer, the reinforcing fibers and the lofting agent, heating the webabove a softening temperature of the thermoplastic polymer of the web,and disposing a film on a first surface of the web to provide acomposite prepreg that can withstand at least 50 individual impactsaccording to a SAE J400 protocol without damage to the disposed film.

In some examples, the method comprises compressing the composite prepregto a predetermined thickness to form a composite article. In otherexamples, the method comprises lofting the composite article to increasethe thickness of the composite article. In further examples, the methodcomprises disposing a scrim on a second surface of the web. In someexamples, the method comprises compressing the composite prepreg to apredetermined thickness to form a composite article. In other examples,the method comprises configuring the thermoplastic polymer as apolypropylene resin, configuring the reinforcing fibers as glass fibersand configuring the lofting agent as microspheres. In certain examples,the method comprises configuring the film as a homopolymer film or acopolymer film. In some embodiments, the method comprises selecting thehomopolymer film to be a polyolefin film. In certain instances, themethod comprises configuring the film to have a thickness of at least 10mils. In other embodiments, the method comprises configuring thethermoplastic resin to be present at 50% by weight or more in theaqueous solution.

In another aspect, a method of forming a composite article comprisescombining a thermoplastic polymer, reinforcing fibers and a loftingagent in an aqueous solution, mixing the aqueous solution comprising thethermoplastic polymer, reinforcing fibers and lofting agent to dispersethe reinforcing fibers and the lofting agent in the thermoplasticpolymer to provide an aqueous foam dispersion, disposing the aqueousfoam dispersion onto a forming element,

removing liquid from the disposed aqueous foam to provide a core layercomprising a web formed from the thermoplastic polymer, the reinforcingfibers and the lofting agent, heating the core layer above a softeningtemperature of the thermoplastic polymer of the core layer, disposing animpact resistant film on a first surface of the core layer, disposing ascrim on a second surface of the core layer to provide a compositearticle, and compressing the composite article to a selected thickness,in which the compressed composite article can withstand at least 50individual impacts according to a SAE J400 protocol without damage tothe disposed film.

In certain embodiments, the method comprises lofting the compositearticle to increase the thickness of the composite article. In otherembodiments, the method comprises selecting the scrim as a scrim thatcomprises glass fibers, aramid fibers, graphite fibers, carbon fibers,inorganic mineral fibers, metal fibers, metalized synthetic fibers, andmetalized inorganic fibers. In some instances, the film and the scrimare simultaneously disposed on the core layer. In other instances, themethod comprises configuring each of the thermoplastic polymer and thelofting agent as particles with about the same average particlediameter. In certain examples, the method comprises configuring thethermoplastic polymer as a polypropylene resin, configuring thereinforcing fibers as glass fibers and configuring the lofting agent asmicrospheres. In additional examples, the method comprises configuringthe film as a homopolymer film or a copolymer film. In some embodiments,the method comprises selecting the homopolymer film to be a polyolefinfilm. In some examples, the method comprises configuring the film tohave a thickness of at least 10 mils. In certain examples, the methodcomprises configuring the thermoplastic resin to be present at 50% byweight or more in the aqueous solution.

In another aspect, a method of reducing drag on a vehicle comprisescoupling an underbody shield to the vehicle, the underbody shieldcomprising a thermoplastic core layer comprising a web of open celledstructures defined by random crossing over of reinforcing fibers heldtogether by a thermoplastic polymer, the thermoplastic core layerfurther comprising a lofting agent effective to increase a thickness ofthe core layer upon exposure to heat to provide a post lofted corelayer, and a film disposed on a first surface of the core layer, inwhich the underbody shield can withstand at least 50 individual impactsaccording to a SAE J400 protocol without damage to the film of theunderbody shield.

In certain examples, the method comprises providing instructions formolding the underbody shield. In other examples, the method comprisesproviding instructions for lofting the core layer of the underbodyshield. In some instances, the method comprises providing at least onefastener configured to couple the underbody shield to the automotivevehicle. In some embodiments, the method comprises instructions forattaching the underbody shield to the automotive vehicle.

In an additional aspect, a method of reducing drag on a vehiclecomprises coupling an underbody shield to the vehicle, the underbodyshield comprising a thermoplastic core layer comprising a web of opencelled structures defined by random crossing over of reinforcing fibersheld together by a thermoplastic polymer, the thermoplastic core layerfurther comprising a lofting agent effective to increase a thickness ofthe core layer upon exposure to heat to provide a post lofted corelayer, a film disposed on a first surface of the core layer and a scrimdisposed on a second surface of the core layer, in which the underbodyshield can withstand at least 50 individual impacts according to a SAEJ400 protocol without damage to the film of the underbody shield.

In some embodiments, the method comprises providing instructions forcuring the prepreg to form an underbody shield. In other embodiments,the method comprises providing instructions for molding the prepreg toform an underbody shield. In some instances, the method comprisesproviding instructions for crosslinking the adhesive layer of theprepreg. In certain examples, the method comprises providinginstructions for lofting the core layer.

In another aspect, a method of reducing drag on a vehicle comprisesproviding an underbody shield comprising a thermoplastic core layercomprising a web of open celled structures defined by random crossingover of reinforcing fibers held together by a thermoplastic polymer, thethermoplastic core layer further comprising a lofting agent effective toincrease a thickness of the core layer upon exposure to heat to providea post lofted core layer, and a film disposed on a first surface of thecore layer, in which the underbody shield can withstand at least 50individual impacts according to a SAE J400 protocol without damage tothe film of the underbody shield.

In certain examples, the method comprises providing instructions formolding the underbody shield. In other examples, the method comprisesproviding instructions for lofting the core layer of the underbodyshield. In some embodiments, the method comprises providing at least onefastener configured to couple the underbody shield to the automotivevehicle. In some instances, the method comprises providing instructionsfor attaching the underbody shield to the automotive vehicle.

In an additional aspect, a method of reducing drag on a vehiclecomprises providing an underbody shield comprising a thermoplastic corelayer comprising a web of open celled structures defined by randomcrossing over of reinforcing fibers held together by a thermoplasticpolymer, the thermoplastic core layer further comprising a lofting agenteffective to increase a thickness of the core layer upon exposure toheat to provide a post lofted core layer, a film disposed on a firstsurface of the core layer and a scrim disposed on a second surface ofthe core layer, in which the underbody shield can withstand at least 50individual impacts according to a SAE J400 protocol without damage tothe film of the underbody shield.

In some examples, the method comprises providing instructions for curingthe prepreg to form an underbody shield. In other examples, the methodcomprises providing instructions for molding the prepreg to form anunderbody shield. In some instances, the method comprises providinginstructions for crosslinking the adhesive layer of the prepreg. Incertain examples, the method comprises providing instructions forlofting the core layer.

In another aspect, a molded composite comprises a fiber reinforcedthermoplastic polymer core, and a film disposed on a surface of thefiber reinforced thermoplastic polymer core, in which the moldedcomposite can withstand at least 50 individual impacts according to aSAE J400 protocol without damage to the film of the underbody shield.

In some instances, the fiber reinforced thermoplastic polymer corecomprises a web of open celled structures defined by random crossingover of reinforcing fibers held together by a thermoplastic polymer. Inother instances, the reinforcing fibers comprise glass fibers. In someexamples, the film comprises a thickness of at least 10 mils. In someembodiments, the thermoplastic polymer is present at 50% by weight ormore and the polymer core further comprises a lofting agent.

In an additional aspect, a molded composite comprises a fiber reinforcedthermoplastic polymer core, a film disposed on a first surface of thefiber reinforced thermoplastic polymer core, and a scrim disposed on asecond surface of the fiber reinforced thermoplastic polymer core, inwhich the molded composite can withstand at least 50 individual impactsaccording to a SAE J400 protocol without damage to the film of theunderbody shield.

In some examples, the fiber reinforced thermoplastic polymer corecomprises a web of open celled structures defined by random crossingover of reinforcing fibers held together by a thermoplastic polymer. Inother examples, the reinforcing fibers comprise glass fibers. In someexamples, the film comprises a thickness of at least 10 mils. In certainexamples, the thermoplastic polymer is present at 50% by weight or moreand the polymer core further comprises a lofting agent.

Additional features, aspect, examples, configurations and embodimentsare described in more detail below.

BRIEF DESCRIPTION OF THE FIGURES

Certain embodiments are described with reference to the accompanyingfigures in which:

FIG. 1 is an illustration of a core layer coupled to a skin layer, inaccordance with certain examples;

FIG. 2 is an illustration of two core layers and a skin layer, inaccordance with certain configurations;

FIG. 3 is an illustration of a composite article including a core layerand two skin layers, in accordance with certain illustrations;

FIG. 4 is an illustration of a composite article including a core layer,two skin layers and a decorative layer, in accordance with certainembodiments;

FIG. 5 is an example of a core layer and two skins layers, in accordancewith certain configurations;

FIG. 6 is an illustration of a core layer, a skin layer, and skin layerstrips in accordance with certain examples;

FIGS. 7A and 7B show illustrations of skin layers smaller than a surfaceof a core layer, in accordance with certain embodiments;

FIGS. 8A-8D show various configurations of a prepreg, in accordance withcertain configurations;

FIG. 9 is an illustration of an article comprising a prepreg or core anda film, in accordance with certain embodiments;

FIG. 10 is an illustration of an article comprising a prepreg or core, afilm and a scrim, in accordance with certain embodiments;

FIG. 11 is an illustration of an article comprising a prepreg or core, afilm, a scrim and a decorative layer, in accordance with certainembodiments; and

FIGS. 12A-12C are photographs of various boards subjected to agravelometer test.

It will be recognized by the person of ordinary skill in the art, giventhe benefit of this disclosure, that certain dimensions or features inthe figures may have been enlarged, distorted or shown in an otherwiseunconventional or non-proportional manner to provide a more userfriendly version of the figures. No particular thickness, width orlength is intended by the depictions in the figures, and relative sizesof the figure components are not intended to limit the sizes of any ofthe components in the figures. Where dimensions or values are specifiedin the description below, the dimensions or values are provided forillustrative purposes only. In addition, no particular material orarrangement is intended to be required by virtue of shading of certainportions of the figures, and even though different components in thefigures may include shading for purposes of distinction, the differentcomponents can include the same or similar materials, if desired.

DETAILED DESCRIPTION

Certain embodiments are described below with reference to singular andplural terms in order to provide a more user friendly description of thetechnology disclosed herein. These terms are used for conveniencepurposes only and are not intended to limit the prepregs, cores,articles, composites, underbody shields and other subject matter asincluding or excluding certain features unless otherwise noted as beingpresent in a particular embodiment described herein.

In certain instances, the materials described herein are typically usedtogether to provide an underbody shield which can be coupled to theunderside of a vehicle. While some illustrations below refer to couplingof an underbody shield to a passenger automobile, the underbody shieldscan also be used in commercial vehicles, recreational vehicles,all-terrain vehicles and in other vehicles comprising a gas engine,hybrid engine, electric engine, fuel cell as an engine and the like.Further, the underbody shields can be used in other areas of the enginecompartment, e.g., as an engine cover or positioned along the side of anengine block, as wheel well liners, as trunk liners or in othervehicular applications where a light weight, impact resistant compositepanel is desired.

Certain configurations described herein refer to impact resistance.Unless otherwise stated, the impact resistance of a particular compositearticle is tested according to the SAE Standard J400 dated Oct. 23, 2012(referred to hereafter as “a gravelometer test”), which is similar toASTM D3170-14 dated Jul. 1, 2014 and entitled “Standard Test Method forChipping Resistance of Coatings.” Even though the aforementioned testswere designed to test impact resistance of surface coatings, they areuseful in evaluating the composite articles for impact resistance. Forexample, the composite article can be tested according to the SAE J400test and may be considered to pass the test if the number of impactcycles exceeds a desired value, e.g., greater than or equal to 50impacts by individual stones, gravels or equivalent flying objects,greater than or equal to 100 impacts by individual stones, gravels orequivalent flying objects, greater than or equal to 200 impacts byindividual stones, gravels or equivalent flying objects, or greater thanor equal to 300 impacts by individual stones, gravels or equivalentflying objects. As discussed in more detail below, by configuring theresin to reinforcing fiber ratio of the core layer and by configuringthe thickness and nature of the skin layer, a light weight compositearticle with high impact resistance can be produced.

Certain configurations are described herein with reference to thearticle comprising a film. The film may be present (or include) ahomopolymer with optionally with one or more additives or a co-polymeroptionally with one or more additives. For example, the film maycomprise a homopolymer or copolymer comprising one or more polyolefinsoptionally with one or more additives such as, for example, colorants,impact modifiers, elastomers, etc. Illustrative polymers which may bepresent in the film or from which the film may be produced include, butare not limited to, one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. As noted below, impact modified films and other films canbe used to provide an article that can meet at least 50 impacts, 100impacts or more according to the SAE Standard J400.

In certain examples, the underbody shield compositions described hereinmay comprise a core layer and a skin layer, e.g., a film or othermaterial which can provide impact resistance to the underbody shield,disposed on the core layer to provide a composite article with an impactresistance of at least 100 individual impacts (according to SAE J400)without any destruction of the skin layer. Referring to FIG. 1, asimplified illustration of an underbody shield board which can be formedinto an underbody shield, e.g., using molding, thermoforming, drawing orother forming processes, is shown. The board 100 comprises a core layer110 and a skin layer 120 disposed on the core layer 110. The skin layer120 is typically a film with a suitable thickness and properties toprovide impact resistance though other materials may instead be used insome configurations. As noted below, however, the core layer 110 canalso impart some impact resistance to the composite article even thoughthe impact is not directly incident on the core layer 110. Theparticular dimensions shown in FIG. 1 have been enlarged forillustration and no particular thickness of one component, relative tothe thickness of another component, is intended to be applied. As notedin more detail below, the core layer 110 generally comprises a web opencelled structures defined by random crossing over of reinforcingmaterials, e.g., reinforcing fibers, held together by a thermoplasticpolymer. In certain instances, the thermoplastic core layer 110 may alsocomprise a lofting agent effective to increase a thickness of the corelayer upon exposure to heat to provide a post lofted core layer. In someinstances, the molding process and the lofting process may be performedtogether, e.g., by placing the board 100 into a heated mold and applyinga sufficient amount of heat to mold the board and loft the core of theboard. The particular amounts and types of materials present in the corelayer 110 and the skin layer 120 are discussed in more detail below. Insome examples, the resin content of the core layer 110 may be increased(compared to a non-impact resistance board), the thickness of the corelayer 110 may be decreased and/or the film thickness can be increased toenhance impact resistance of the board 100. For example, the core layermay comprise a higher polymer to reinforcing material ratio (e.g.,greater than or equal to 50% by weight thermoplastic polymer in the corelayer 110). As noted below, a higher polymer resin amount present in acore layer adjacent to a film can increase the impact resistance of thecomposite article. Alternatively or in addition to the higher polymercontent, the overall thickness of a core layer adjacent to a skin layer120 may be decreased to provide for enhanced impact strength.Unexpectedly, by decreasing the overall thickness of the core layer 110,impact resistance of the composite article can be increased. Inaddition, selection of skin layer properties and/or thickness incombination with a decreased thickness core layer may further enhanceimpact resistance of the article. In some configurations, a core layer110 may comprise at least 50 weight percent or at least 55 weightpercent thermoplastic polymer. The balance of the core layer 110 maycomprise reinforcing materials and/or a lofting agent. For example,glass fibers may be present in the core layer 110 up to about 30-45weight percent, and a lofting agent may be present from about 0 weightpercent to about 15 weight percent. In certain examples, the skin layer120 may be a film (or may comprise a film) with a thickness of 10 milsor more, and the composite article formed using the layers 110, 120 maywithstand at least 50 impacts by individual stones, gravels orequivalent flying objects as tested using a gravelometer test. Forexample, the film 120 may comprise a homopolymer or copolymer such as apolyolefin homopolymer or a polyolefin copolymer (optionally with one ormore additives) that provides impact resistance. Illustrativehomopolymers for the film 120, include but are not limited to,polyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate homopolymers. Where acopolymer is present in the film 120, the copolymers may be produced,for example, using one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. The exact thickness of the film can vary and in someinstances the film is desirably thick enough to provide at least 50impacts (to the article comprising the film) under the SAE J400protocol. The film thickness can vary, for example, based on thethickness and properties of the core layer. In some embodiments, thefilm 120 is at least about 10 mils thick, more particularly, 12 mils,thick, 14 mils thick, 16 mils thick, 18 mils thick or 20 mils thick ormore.

In certain configurations, the core layer can be split into two or moreseparate core layers if desired. While in some instances, a first andsecond core layer may comprise the same polymer and/or reinforcingmaterials, the reinforcing materials and/or polymer of the differentcore layers can be different if desired. Referring to FIG. 2, an article200 is shown comprising a first core layer 210 and a second core layer220. A skin layer 230, e.g., impact resistance film, is disposed on thecore layer 210. Where two or more core layers are present, the corelayer adjacent to the skin layer 230 may comprise a higher polymer toreinforcing material ratio than other core layers. As noted herein, ahigher polymer resin amount present in a core layer adjacent to a skinlayer, e.g., a film, can increase the impact resistance of the article.Alternatively or in addition to the higher polymer content, the overallthickness of a core layer adjacent to a skin layer 230 may be decreasedto provide for enhanced impact strength. By decreasing the overallthickness of the core layer 210, impact resistance can be increased. Inaddition, selection of film properties and/or thickness in combinationwith a decreased thickness core layer may further enhance impactresistance of the article. In some embodiments, the combination of thefirst core layer 210 and the second core layer 220 may provide anoverall desired thickness with the second core layer 220 being thickerthan the first core layer 210. In certain configurations, the core layer210 may comprise at least 50 weight percent may comprise at least 50weight percent or at least 55 weight percent thermoplastic polymer. Thebalance of the core layer 210 may comprise reinforcing materials and/ora lofting agent. For example, glass fibers may be present in the corelayer 210 up to about 30-45 weight percent, and a lofting agent may bepresent from about 0 weight percent to about 15 weight percent. The corelayer 220 may be configured similar to the core layer 210 or maycomprise a lower weight percent thermoplastic polymer, e.g., less than50 weight percent thermoplastic polymer. The reinforcing materialpresent in the core layers 210, 220 may be the same or may be different,e.g., may both be glass fibers. In some instances, one of the corelayers 210, 220 may comprise more lofting agent such that increasedthickness can be achieved by lofting one of the core layers 210, 220.For example, in some configurations, the core layer 220 may comprisemore lofting agent than the core layer 210, whereas in otherconfigurations, the core layer 210 may comprise more lofting agent thanthe core layer 220. While not wishing to be bound by any particulartheory, by including more lofting agent in the core layer 210, duringthe lofting process expansion of the core layer 210 can result in highercompression ratio for the molding process which enhances bonding betweenthe two layers 210, 230. The skin layer 230 may be a film (or maycomprise a film) with a thickness of 10 mils or more, and the compositearticle formed using the layers 210-230 may withstand at least 50impacts by individual stones, gravels or equivalent flying objects astested using a gravelometer test. In some configurations, the film 230may comprise a homopolymer or copolymer such as a polyolefin (optionallywith one or more additives) that provides impact resistance.Illustrative homopolymers for the film 230, include but are not limitedto, polyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate homopolymers. Where acopolymer is present in the film 230, the copolymers may be produced,for example, using one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. The exact thickness of the film can vary and in someinstances the film is desirably thick enough to provide at least 50impacts (to the article comprising the film) under the SAE J400protocol. The film thickness can vary, for example, based on thethickness and properties of the core layer. In some embodiments, thefilm 230 is at least about 10 mils thick, more particularly, 12 mils,thick, 14 mils thick, 16 mils thick, 18 mils thick or 20 mils thick ormore.

In certain configurations, materials for use as an underbody shieldmaterial may include a core layer, a first skin layer and a second skinlayer. Referring to FIG. 3, an underbody shield board 300 is showncomprising a core layer 310, a first skin layer 320 disposed on onesurface and a second skin layer 330 disposed on another surface. Whilethe first and second skin layers 320, 330 may be the same, in a typicalconfiguration, the skin layer 320 is selected to provide impactresistance and the skin layer 330 is selected for properties other thanimpact resistance, e.g., to provide acoustics properties, flameretardancy, liquid absorption, aesthetic features, etc. In use of theboard 300, the skin layer 320 is typically exposed to the outsideenvironment and may receive impacts from gravel or other debris in itsuse environment. The particular dimensions shown in FIG. 3 have beenenlarged for illustration and no particular thickness of one component,relative to the thickness of another component, is intended to beapplied. For example, the skin layers 320, 330 may have the same or adifferent thickness. The core layer 310 generally comprises a web opencelled structures defined by random crossing over of reinforcingmaterials, e.g., reinforcing fibers, held together by a thermoplasticpolymer. In certain instances, the thermoplastic core layer 310 may alsocomprise a lofting agent effective to increase a thickness of the corelayer 310 upon exposure to heat to provide a post lofted core layer. Insome instances, the molding process and the lofting process may beperformed together, e.g., by placing the board 300 into a heated moldand applying a sufficient amount of heat to mold the board and loft thecore of the board. In some examples, the resin content of the core layer310 may be increased (compared to a non-impact resistance board), thethickness of the core layer 310 may be decreased and/or the filmthickness of the layer 320 can be increased to enhance impact resistanceof the board 300. For example, the core layer 310 may comprise a higherpolymer to reinforcing material ratio (e.g., greater than or equal to50% by weight thermoplastic polymer in the core layer 310). As notedbelow, a higher polymer resin amount present in a core layer 310adjacent to a skin layer 320 comprising a film can increase the impactresistance of the composite article. Alternatively or in addition to thehigher polymer content, the overall thickness of a core layer 310adjacent to the skin layer 320 may be decreased to provide for enhancedimpact strength. In some configurations, by decreasing the overallthickness of the core layer 310, impact resistance of the compositearticle can be increased. In addition, selection of skin layerproperties and/or thickness in combination with a decreased thicknesscore layer 310 may further enhance impact resistance of the article. Insome configurations, a core layer 310 may comprise at least 50 weightpercent or at least 55 weight percent thermoplastic polymer. The balanceof the core layer 310 may comprise reinforcing materials and/or alofting agent. For example, glass fibers may be present in the corelayer 310 up to about 30-45 weight percent, and a lofting agent may bepresent from about 0 weight percent to about 15 weight percent. In someinstances, the skin layer 320 may be a film (or may comprise a film)with a thickness of 10 mils or more. In certain embodiments, the layer330 may comprise a scrim. In some examples, a composite article formedusing the layers 310, 320 and 330 may withstand at least 50 impacts byindividual stones, gravels or equivalent flying objects as tested usinga gravelometer test. In some configurations, the film 320 may comprise ahomopolymer such as a polyolefin (optionally with one or more additives)that provides impact resistance. Illustrative homopolymers for the film320, include but are not limited to, polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate homopolymers. Where a copolymer is present in the film 320,the copolymers may be produced, for example, using one or more ofpolyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate. The exact thickness of thefilm can vary and in some instances the film is desirably thick enoughto provide at least 50 impacts (to the article comprising the film)under the SAE J400 protocol. The film thickness can vary, for example,based on the thickness and properties of the core layer. In someembodiments, the film 320 is at least about 10 mils thick, moreparticularly, 12 mils, thick, 14 mils thick, 16 mils thick, 18 milsthick or 20 mils thick or more.

In certain embodiments, the components of the boards shown in FIGS. 1-3may be coupled to each other without the use of any intervening adhesivelayer. In many composite article constructions, an adhesive layer ispresent to enhance bonding between the various components. In certainembodiments of the articles described herein, the components aredirectly coupled to each other without any intervening adhesive layer orother layers. For example, a skin layer can be disposed directly on asurface of the core layer. The construct may be heated and/or compressedto bond the skin layer directly to the core layer without the use of anadhesive layer. Similarly, where two or more core layers are present,the core layers can be directly coupled to each other without the use ofan adhesive layer between them. Where a skin layer is disposed on eachsurface of a core layer, each of the skin layers may be directly coupledto the core layers without an intervening adhesive layer or one of theskins may be coupled to the core layer using an adhesive layer. Forexample, a scrim can be coupled to a core layer through an adhesivelayer on one surface of the core layer, and an impact resistant film canbe coupled to the core layer on an opposite surface without the use ofany intervening adhesive layer. As noted in more detail below, thevarious components may be coupled to each other when the core layer isformed and still in a “soft” or melted state or after the core layer hasbeen formed.

In certain embodiments and referring to FIG. 4, a board 400 is showncomprising a core layer 410, a first skin layer 420, a second skin layer430 and an adhesive layer between the core layer 410 and the second skinlayer 430. The first and second skin layers 420, 430 may be the same ordifferent. For example, the skin layer 420 can be selected to provideimpact resistance, and the skin layer 430 can be selected for propertiesother than impact resistance, e.g., to provide acoustics properties,flame retardancy, liquid absorption, aesthetic features, etc. In use ofthe board 400, the skin layer 420 is typically exposed to the outsideenvironment and may receive impacts from gravel or other debris in itsuse environment. The particular dimensions shown in FIG. 4 have beenenlarged for illustration and no particular thickness of one component,relative to the thickness of another component, is intended to beapplied. For example, the skin layers 420, 430 may have the same or adifferent thickness. The core layer 410 generally comprises a web opencelled structures defined by random crossing over of reinforcingmaterials, e.g., reinforcing fibers, held together by a thermoplasticpolymer. In certain instances, the thermoplastic core layer 410 may alsocomprise a lofting agent effective to increase a thickness of the corelayer 410 upon exposure to heat to provide a post lofted core layer. Insome instances, the molding process and the lofting process may beperformed together, e.g., by placing the board 400 into a heated moldand applying a sufficient amount of heat to mold the board and loft thecore of the board. In some examples, the resin content of the core layer410 may be increased (compared to a non-impact resistance board), thethickness of the core layer 410 may be decreased and/or the thickness ofthe layer 420 can be increased to enhance impact resistance of the board400. For example, the core layer 410 may comprise a higher polymer toreinforcing material ratio (e.g., greater than or equal to 50% by weightthermoplastic polymer in the core layer 410). As noted below, a higherpolymer resin amount present in a core layer 410 adjacent to a skinlayer 420 comprising a film can increase the impact resistance of thecomposite article. Alternatively or in addition to the higher polymercontent, the overall thickness of a core layer 410 adjacent to the skinlayer 420 may be decreased to provide for enhanced impact strength. Insome configurations, by decreasing the overall thickness of the corelayer 410, impact resistance of the composite article can be increased.In addition, selection of skin layer properties and/or thickness incombination with a decreased thickness core layer 410 may furtherenhance impact resistance of the article. In some configurations, a corelayer 410 may comprise at least 50 weight percent or at least 55 weightpercent thermoplastic polymer. The balance of the core layer 410 maycomprise reinforcing materials and/or a lofting agent. For example,glass fibers may be present in the core layer 410 up to about 30-45weight percent, and a lofting agent may be present from about 0 weightpercent to about 15 weight percent. In some instances, the skin layer420 may be a film (or may comprise a film) with a thickness of 10 milsor more. In certain embodiments, the layer 430 may comprise a scrim. Insome configurations, the adhesive layer 440 may comprise a thermoplasticpolymer adhesive and/or a thermoset adhesive. In certain embodiments,the adhesive layer 440 may comprise a polyolefin thermoplastic adhesive.In some examples, a composite article formed using the layers 410, 420,430 and 440 may withstand at least 50 impacts by individual stones,gravels or equivalent flying objects as tested using a gravelometertest. In some configurations, the film 420 may comprise a homopolymersuch as a polyolefin (optionally with one or more additives) thatprovides impact resistance. Illustrative homopolymers for the film 420,include but are not limited to, polyethylene, polypropylene, polyamide,polyethylene terephthalate, polycarbonate and polymethyl methacrylatehomopolymers. Where a copolymer is present in the film 420, thecopolymers may be produced, for example, using one or more ofpolyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate. The exact thickness of thefilm can vary and in some instances the film is desirably thick enoughto provide at least 50 impacts (to the article comprising the film)under the SAE J400 protocol. The film thickness can vary, for example,based on the thickness and properties of the core layer. In someembodiments, the film 420 is at least about 10 mils thick, moreparticularly, 12 mils, thick, 14 mils thick, 16 mils thick, 18 milsthick or 20 mils thick or more.

In certain configurations, one or more areas of the board may comprisereinforcement or strips disposed on a surface of a core layer and/or theskin layers. For example, while the skin layer exposed to impactstypically is a continuous layer across a planar surface of a core layer,the thickness of the skin layer need not be the same at all areas acrossthe board. Certain areas may comprise increased thickness, e.g., areasof the board that are used to fasten an underbody shied to a vehicle maybe thicker than other areas. In some instances, the variability inthickness can be achieved by disposing two or more skin layers onto eachother. Referring to FIG. 5, a board 500 is shown comprising a core layer510, and skin layers 520, 530. The skin layer 520 is typically selectedto provide impact resistance to the board 500.

The particular dimensions shown in FIG. 5 have been enlarged forillustration and no particular thickness of one component, relative tothe thickness of another component, is intended to be applied. Forexample, the skin layers 520, 530 may have the same or a differentthickness. The core layer 510 generally comprises a web open celledstructures defined by random crossing over of reinforcing materials,e.g., reinforcing fibers, held together by a thermoplastic polymer. Incertain instances, the thermoplastic core layer 510 may also comprise alofting agent effective to increase a thickness of the core layer 510upon exposure to heat to provide a post lofted core layer. In someinstances, the molding process and the lofting process may be performedtogether, e.g., by placing the board 500 into a heated mold and applyinga sufficient amount of heat to mold the board and loft the core of theboard. In some examples, the resin content of the core layer 510 may beincreased (compared to a non-impact resistance board), the thickness ofthe core layer 510 may be decreased and/or the thickness of the layer520 can be increased to enhance impact resistance of the board 500. Forexample, the core layer 510 may comprise a higher polymer to reinforcingmaterial ratio (e.g., greater than or equal to 50% by weightthermoplastic polymer in the core layer 510). As noted below, a higherpolymer resin amount present in a core layer 510 in combination with askin layer 520 comprising a film can increase the impact resistance ofthe composite article. Alternatively or in addition to the higherpolymer content, the overall thickness of a core layer 510 may bedecreased to provide for enhanced impact strength. In someconfigurations, by decreasing the overall thickness of the core layer510, impact resistance of the composite article can be increased. Inaddition, selection of skin layer properties and/or thickness incombination with a decreased thickness core layer 510 may furtherenhance impact resistance of the article. In some configurations, a corelayer 510 may comprise at least 50 weight percent or at least 55 weightpercent thermoplastic polymer. The balance of the core layer 510 maycomprise reinforcing materials and/or a lofting agent. For example,glass fibers may be present in the core layer 510 up to about 30-45weight percent, and a lofting agent may be present from about 0 weightpercent to about 15 weight percent. In some instances, the skin layer520 may be a film (or may comprise a film) with a thickness of 10 milsor more. In certain embodiments, the skin layer 530 may comprise asecond film which may or may not be an impact resistance film. In someexamples, a composite article formed using the layers 510, 520, and 530may withstand at least 50 impacts by individual stones, gravels orequivalent flying objects as tested using a gravelometer test. While notshown, the core layer 510 may comprise a scrim disposed on an oppositesurface similar to the scrim 330 present in FIG. 3. In certainconfigurations, the film 520 may comprise a homopolymer such as apolyolefin (optionally with one or more additives) that provides impactresistance. Illustrative homopolymers for the film 520, include but arenot limited to, polyethylene, polypropylene, polyamide, polyethyleneterephthalate, polycarbonate and polymethyl methacrylate homopolymers.Where a copolymer is present in the film 520, the copolymers may beproduced, for example, using one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. The exact thickness of the film can vary and in someinstances the film is desirably thick enough to provide at least 50impacts (to the article comprising the film) under the SAE J400protocol. The film thickness can vary, for example, based on thethickness and properties of the core layer. In some embodiments, thefilm 520 is at least about 10 mils thick, more particularly, 12 mils,thick, 14 mils thick, 16 mils thick, 18 mils thick or 20 mils thick ormore.

In certain configurations, a second skin layer may only be present atcertain areas of an underbody shield. Referring to FIG. 6, a board 600is shown comprising a core layer 610, a skin layer 620 and skin layerstrips 630 a, 630 b. While strips 630 a, 630 b are shown as beingdisposed on outer edges of the skin layer 620, they may instead bedisposed in other areas as desired. Further, the exact number of stripspresent may vary from one up to ten or more. As noted herein, it may bedesirable to include strips at coupling sites to provide for higherstrength areas for regions where the underbody shield couples to avehicle. The skin strips 630 a, 630 b may have the same or a differentthickness and may comprise a similar or a different composition. In use,the strips 630 a, 630 b may not be positioned in areas that willexperience impacts. Instead, the skin layer 620 can be selected to beimpact resistant with the skins 630 a, 630 b being present in non-impactareas of the board 600. The core layer 610 generally comprises a webopen celled structures defined by random crossing over of reinforcingmaterials, e.g., reinforcing fibers, held together by a thermoplasticpolymer. In certain instances, the thermoplastic core layer 610 may alsocomprise a lofting agent effective to increase a thickness of the corelayer 610 upon exposure to heat to provide a post lofted core layer. Insome instances, the molding process and the lofting process may beperformed together, e.g., by placing the board 600 into a heated moldand applying a sufficient amount of heat to mold the board and loft thecore of the board. In some examples, the resin content of the core layer610 may be increased (compared to a non-impact resistance board), thethickness of the core layer 610 may be decreased and/or the thickness ofthe layer 620 can be increased to enhance impact resistance of the board600. For example, the core layer 610 may comprise a higher polymer toreinforcing material ratio (e.g., greater than or equal to 50% by weightthermoplastic polymer in the core layer 610). As noted below, a higherpolymer resin amount present in a core layer 610 in combination with askin layer 620 comprising a film can increase the impact resistance ofthe composite article. Alternatively or in addition to the higherpolymer content, the overall thickness of a core layer 610 may bedecreased to provide for enhanced impact strength. In someconfigurations, by decreasing the overall thickness of the core layer610, impact resistance of the composite article can be increased. Inaddition, selection of skin layer properties and/or thickness incombination with a decreased thickness core layer 610 may furtherenhance impact resistance of the article. In some configurations, a corelayer 610 may comprise at least 50 weight percent or at least 55 weightpercent thermoplastic polymer. The balance of the core layer 610 maycomprise reinforcing materials and/or a lofting agent. For example,glass fibers may be present in the core layer 610 up to about 30-45weight percent, and a lofting agent may be present from about 0 weightpercent to about 15 weight percent. In some instances, the skin layer620 may be a film (or may comprise a film) with a thickness of 10 milsor more. In certain embodiments, the skin strips 630 a, 630 b may alsocomprise a film, a scrim or other suitable skin layers. In someexamples, a composite article formed using the layers 610, 620, and 630a, 630 b may withstand at least 50 impacts by individual stones, gravelsor equivalent flying objects as tested using a gravelometer test. Whilenot shown, the core layer 610 may comprise a scrim disposed on anopposite surface similar to the scrim 330 present in FIG. 3. In certainconfigurations, the film 620 may comprise a homopolymer such as apolyolefin (optionally with one or more additives) that provides impactresistance. Illustrative homopolymers for the film 620, include but arenot limited to, polyethylene, polypropylene, polyamide, polyethyleneterephthalate, polycarbonate and polymethyl methacrylate homopolymers.Where a copolymer is present in the film 620, the copolymers may beproduced, for example, using one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. The exact thickness of the film 620 can vary and in someinstances the film is desirably thick enough to provide at least 50impacts (to the article comprising the film) under the SAE J400protocol. The film thickness can vary, for example, based on thethickness and properties of the core layer. In some embodiments, thefilm 620 is at least about 10 mils thick, more particularly, 12 mils,thick, 14 mils thick, 16 mils thick, 18 mils thick or 20 mils thick ormore.

In certain instances, the skin layer need not traverse the entiresurface of the core layer. For example and referring to FIG. 7A, a board700 comprising a core layer 710 and a skin layer 720 disposed on thecore layer 710 is shown. The outer edges of the core layer 710 do notcomprise any skin layer 720. To reduce overall weight and/or productioncost, it may be desirable to dispose an impact resistant skin layer onlyin areas that are likely to experience significant impacts. Non-impactareas may be filled in with other materials such as films, scrims andthe like. For example and referring to FIG. 7B, a board 750 is shownthat comprises strips 730 a, 730 b adjacent to the skin layer 720. Theexact nature and thickness of the strips 730 a, 730 b may vary, and thedifferent strips 730 a, 730 b may have a similar or differentcomposition and a similar or different thickness or other physicalproperties. Similar to the other core layers described herein, the corelayer 710 generally comprises a web open celled structures defined byrandom crossing over of reinforcing materials, e.g., reinforcing fibers,held together by a thermoplastic polymer. In certain instances, thethermoplastic core layer 710 may also comprise a lofting agent effectiveto increase a thickness of the core layer 710 upon exposure to heat toprovide a post lofted core layer. In some instances, the molding processand the lofting process may be performed together, e.g., by placing theboard 700 or 750 into a heated mold and applying a sufficient amount ofheat to mold the board and loft the core of the board. In some examples,the resin content of the core layer 710 may be increased (compared to anon-impact resistance board), the thickness of the core layer 710 may bedecreased and/or the thickness of the layer 720 can be increased toenhance impact resistance of the board 700 or 750. For example, the corelayer 710 may comprise a higher polymer to reinforcing material ratio(e.g., greater than or equal to 50% by weight thermoplastic polymer inthe core layer 710). As noted below, a higher polymer resin amountpresent in a core layer 710 in combination with a skin layer 720comprising a film can increase the impact resistance of the compositearticle. Alternatively or in addition to the higher polymer content, theoverall thickness of a core layer 710 may be decreased to provide forenhanced impact strength. In some configurations, by decreasing theoverall thickness of the core layer 710, impact resistance of thecomposite article can be increased. In addition, selection of skin layerproperties and/or thickness in combination with a decreased thicknesscore layer 710 may further enhance impact resistance of the article. Insome configurations, a core layer 710 may comprise at least 50 weightpercent or at least 55 weight percent thermoplastic polymer. The balanceof the core layer 610 may comprise reinforcing materials and/or alofting agent. For example, glass fibers may be present in the corelayer 610 up to about 30-45 weight percent, and a lofting agent may bepresent from about 0 weight percent to about 15 weight percent. In someinstances, the skin layer 720 may be a film (or may comprise a film)with a thickness of 10 mils or more. In certain embodiments, the skinstrips 730 a, 730 b may also comprise a film, a scrim or other suitableskin layers. In some examples, a composite article formed using thelayers 710, 720, and optionally 730 a, 730 b may withstand at least 50impacts by individual stones, gravels or equivalent flying objects astested using a gravelometer test. While not shown, the core layer 710may comprise a scrim disposed on an opposite surface similar to thescrim 330 present in FIG. 3, e.g., either of the boards 700 or 750 maycomprise a scrim or other layer disposed on a surface of the core layer710. In certain configurations, the film 720 may comprise a homopolymersuch as a polyolefin (optionally with one or more additives) thatprovides impact resistance. Illustrative homopolymers for the film 720,include but are not limited to, polyethylene, polypropylene, polyamide,polyethylene terephthalate, polycarbonate and polymethyl methacrylatehomopolymers. Where a copolymer is present in the film 720, thecopolymers may be produced, for example, using one or more ofpolyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate. The exact thickness of thefilm can vary and in some instances the film is desirably thick enoughto provide at least 50 impacts (to the article comprising the film)under the SAE J400 protocol. The film thickness can vary, for example,based on the thickness and properties of the core layer. In someembodiments, the film 720 is at least about 10 mils thick, moreparticularly, 12 mils, thick, 14 mils thick, 16 mils thick, 18 milsthick or 20 mils thick or more.

The underbody shields described herein are often molded or processedinto various shapes to provide a final formed part or article. Duringprocessing, it may be desirable to increase the overall thickness of oneor more components or layers of the article to be processed. In someconfigurations described herein, the presence of a lofting agent in athermoplastic prepreg or a thermoplastic core permits alteration of theoverall thickness of the article (or a portion thereof) during heating,molding or other temperature or processing operations. In someinstances, the lofting agent can be dispersed, e.g., in a substantiallyuniform distribution from surface to surface if desired, in void spaceof a thermoplastic prepreg or core comprising a thermoplastic materialand a plurality of fibers. In certain examples, the lofting agent may bepresent in the prepreg or core but not covalently bonded to the othermaterials in the prepreg or core. In further examples, the lofting agentmay be covalently bonded to one or more groups present in thethermoplastic material or covalently bonded to one or more groups of theplurality of fibers or both. The exact lofting temperature used can varydepending on the other materials present in the prepregs, cores andarticles, and in some instances, the lofting temperature may be greaterthan or equal to the melting point temperature of the thermoplasticmaterial(s) present in the prepregs, cores and articles.

In certain configurations, the articles described herein, e.g.,underbody shields, can comprise a prepreg or core layer. While notwishing to be bound by any particular theory, a prepreg is generally nota fully cured or processed version of a core. For example, a partiallycured layer comprising a thermoplastic material, a plurality ofreinforcing fibers and a lofting agent is generally referred to as aprepreg, whereas a fully cured layer (which may or may not yet belofted) comprising thermoplastic material, a plurality of reinforcingmaterials such as fibers and a lofting agent is generally referred to asa core or core layer. As noted herein, even though the core may beconsidered cured, the core can still be further processed to increaseits thickness, to alter its shape or to otherwise provide a formedarticle or product suitable for an intended use. The description belowmakes reference to both a prepreg and a core and the materials (andtheir amounts and properties) used in connection with a prepreg can alsobe used in a core if desired.

In certain configurations described herein, a suitable amount of alofting agent is included in the prepregs core and articles to providefor selective lofting of the prepregs, cores and articles. Loftinggenerally refers to an overall increase in thickness of the prepreg,core or article during or after a processing condition, e.g.,application of heat and/or pressure. For example, a lofting agent can beselected such that the prepreg, core or article is substantiallyinsensitive to loft at a first temperature and/or first heatingconditions and then is sensitive to loft at a second temperature and/orsecond heating conditions. In certain automotive applications, thelofting agent can be selected to not substantially loft at 180-190 or190-200 deg. Celsius and to loft at 210 or 220 deg. Celsius. While notwishing to be bound by any particular theory, the first and secondtemperatures can vary depending on the thermoplastic material present inthe prepreg, core or article. In certain instances, the lofting agent isselected such that substantially no loft occurs until the lofttemperature is about 20 deg. Celsius or more higher than the meltingpoint of the thermoplastic material in the prepreg or core layer. Inother instances, the lofting agent is selected such that substantiallyno loft occurs until the loft temperature is about 40 deg. Celsius ormore higher than the melting point of the thermoplastic material in thecore layer. In further instances, the lofting agent (and/or the loftingconditions) is selected such that substantially no loft occurs until theloft temperature is about 60 deg. Celsius or more higher than themelting point of the thermoplastic material of the core layer. In someinstances, the lofting agent is selected such that substantially no loftoccurs until the loft temperature is about 80 deg. Celsius or morehigher than the melting point of the thermoplastic material in the corelayer.

In certain examples, the lofting agent of the prepregs and coresdescribed herein may comprise one or more liquid hydrocarbon-polymershell materials. The exact type of lofting agent used in the core candepend on numerous factors including, for example, the desired loftingtemperature, the desired basis weight, desired processing conditions andother factors. Illustrative commercially available lofting agents thatcan be present in a prepreg or core are commercially available fromKureha Corp. (Japan) and include, for example, H1100 liquid hydrocarboncore-polymer microspheres. The lofting agent can be present in manyforms including fiber form, particle form, microsphere form or otherforms. In some instances, the lofting agent can be present inmicrosphere form and may comprise an average particle size of at least40 microns, for example, or may comprise an average particle size thatis substantially similar to the average particle size of thermoplasticmaterial in the core. In some examples, the lofting agent may be presentfrom about 2 weight percent to about 20 weight percent, though dependingon the desired degree of loft, more or less lofting agent can be used inthe prepreg or core. While not wishing to be bound by any particulartheory, liquid hydrocarbon-polymer shell materials can provide somesoftness or flexural properties to the core to permit the core to flexand/or absorb some of the impact energy received by the skin layer. Thisenergy absorption can further enhance the impact resistance of theunderbody shield materials.

In certain configurations, a porous prepreg comprising one or morethermoplastic materials and a plurality of reinforcing materials, e.g.,reinforcing fibers, that together have an open cell structure, e.g.,void space, can be produced. In some configurations, a lofting agent canbe loaded into the void space in a manner where the lofting agentgenerally does not covalently bond with the thermoplastic materialsand/or the fibers. For example, the thermoplastic materials and/or thefibers can be selected so that they are generally inert or non-reactivewith the lofting agent. Even though the lofting agent may not covalentlybond to the thermoplastic material and/or the fibers, there can becovalent bonding present in or within the lofting agent itself. In otherinstances, it may be desirable to covalently bond the lofting agent tothe thermoplastic materials, the fibers or both to provide somecovalently bonded lofting agent in the prepreg. Even where bondedlofting agent is present, the lofting agent desirably can still increasetheir occupied volume under suitable conditions such as, for example,convection heating to permit lofting of the prepreg. In some instances,both covalently bonded lofting agent and non-covalently bonded loftingagent materials may also be present in the prepreg. While someconfigurations of the prepregs may comprise lofting agent where about100% of the lofting agent materials are non-covalently bonded, weakinteractions such as van der Waals' interactions or electrostaticinteractions can take place between the lofting agent and the othercomponents of the prepreg.

In certain examples and referring to FIG. 8A, a prepreg 800 is shownthat comprises a thermoplastic material and a plurality of reinforcingfibers. The prepreg 800 also comprises a lofting agent (shown forillustration purposes as dots 805) dispersed through the prepreg 800. Insome instances, the lofting agent dispersion can be substantiallyhomogeneous or substantially uniform from a first surface 802 to asecond surface 804 of the prepreg 800. As described in more detailherein, to achieve such substantially homogeneous or substantiallyuniform distribution of lofting agent in the prepreg 800, the componentsof the prepreg 800 can be mixed together to form a substantially uniformdispersion. Mixing can be performed until the dispersion comprises asubstantially homogeneous or substantially uniform mixture of thelofting agent, the thermoplastic materials and the fibers in thedispersion. The prepreg 800 may then be formed as described herein,e.g., by disposing the dispersion on a wire screen using a suitablelaying process. In other configurations, it may be desirable to providea gradient distribution of lofting agent from the surface 802 to thesurface 804 such that more lofting agent materials are present towardone of the surfaces 802, 804 than the other surface. In someembodiments, a substantially uniform distribution of lofting agent ispresent in a prepreg 800 and then additional lofting agent is added toone side of the prepreg 800 to provide a gradient distribution. Suchadditional lofting agent can be added directly to the prepreg 800, e.g.,by spraying or coating a solution comprising the lofting agent, or canbe added by coupling a skin, additional prepreg or other componentcomprising lofting agent to the prepreg 800. For example and referringto FIG. 8B, a first prepreg 810 and a second prepreg 820 disposed on thefirst prepreg 810 is shown. Each of the first prepreg 810 and the secondprepreg 820 comprises a substantially uniform distribution of loftingagent, but the amount of lofting agent in the prepregs 810, 820 isdifferent. If desired, however, only one of the prepregs 810, 820 maycomprise a lofting agent and the other prepreg may not comprise alofting agent or may comprise a different lofting agent. Thethermoplastic materials of the prepregs 810, 820 can be melted toprovide a single prepreg 850 (FIG. 8C). The result of melting of theprepregs 810, 820 together is a gradient distribution of lofting agentin the prepreg 850 with increased amounts of lofting agent adjacent to asurface 852 as compared to the amount present adjacent to a surface 854.The exact overall thickness of the prepreg 850 may vary depending on theconditions used and no particular thickness is intended to be implied inFIG. 8B.

In other configurations, a distribution of lofting agent in a prepregcan be provided by coupling a skin or other material comprising loftingagent to the prepreg. Referring to FIG. 8C, a skin 870 comprisinglofting agent is shown as being disposed on a prepreg 860 comprising athermoplastic material, reinforcing fibers and lofting agent. While notrequired, the skin 870 is typically present at a much lower thicknessthan a pre-lofted thickness of the prepreg 860. In addition, adiscernible interface is typically present between the skin 870 and theprepreg 860, whereas coupling of two prepregs to each other, asdescribed in connection with FIG. 8B, generally does not result in anydiscernible interface in the finally coupled prepreg 850. In otherinstances, the skin 870 can be melted into the prepreg 860 to couple theskin 870 and the prepreg 860 to leave a coupled skin/prepreg compositematerial without any substantial interface. If desired and as describedin more detail below, an additional skin, which may or may not compriselofting agent, can also be coupled to the prepreg on an opposite sidefrom the skin 870.

In certain configurations, the thermoplastic material of the prepreg maybe present in fiber form, particle form, resin form or other suitableforms. In some instances, the thermoplastic material used in the prepregcan be present in particle form and have an average particle size thatis substantially the same as the average particle size of the loftingagent. While not wishing to be bound by any particular scientifictheory, by matching the particles sizes of the thermoplastic materialand the lofting agent, enhanced processing of the prepregs including,for example, increased retention of the lofting agent in the prepreg canbe achieved. In some instances, the average particle size of the loftingagent and the average particle size of the thermoplastic material canvary by about 5% to about 10% and enhanced processing can still beachieved. In certain configurations, the average particle size of eachof the thermoplastic material and the lofting agent in the prepreg candiffer by about 50 microns to about 120 microns. In some configurations,the average particle size of the lofting agent is at least 50% of theaverage particle size of the thermoplastic material particles to providefor enhanced processing. In other instances, lofting agent with anaverage particle size about the same as the average particle size of thethermoplastic material can be present along with lofting agent of anaverage particle size that is different than the average particle sizeof the thermoplastic material. Even though the average particle size ofthe lofting agent may differ, the chemical composition of the loftingagent can be the same or can be different. In yet other configurations,two or more thermoplastic materials with different average particlesizes can be present. If desired, two lofting agents with averageparticle sizes that are substantially the same as the average particlesizes of the thermoplastic materials can be present. The two loftingagents may be chemically the same or may be chemically distinct.Similarly, the thermoplastic materials can be chemically the same (buthave a different average particle size) or can be chemically distinct.

In certain embodiments, the prepreg or core 700 generally comprises asubstantial amount of open cell structure such that void space ispresent in the prepreg. For example, the prepreg or core layer maycomprise a void content or porosity of 0-30%, 10-40%, 20-50%, 30-60%,40-70%, 50-80%, 60-90%, 0-40%, 0-50%, 0-60%, 0-70%, 0-80%, 0-90%,10-50%, 10-60%, 10-70%, 10-80%, 10-90%, 10-95%, 20-60%, 20-70%, 20-80%,20-90%, 20-95%, 30-70%, 30-80%, 30-90%, 30-95%, 40-80%, 40-90%, 40-95%,50-90%, 50-95%, 60-95% 70-80%, 70-90%, 70-95%, 80-90%, 80-95% or anyillustrative value within these exemplary ranges. In some instances, theprepreg comprises a porosity or void content of greater than 0%, e.g.,is not fully consolidated, up to about 95%. Unless otherwise stated, thereference to the prepreg comprising a certain void content or porosityis based on the total volume of the prepreg and not necessarily thetotal volume of the prepreg plus any other materials or layers coupledto the prepreg.

In certain embodiments, the high porosity present in the prepreg or corepermits trapping of lofting agent within the pores of the prepreg. Forexample, lofting agent can reside in the void space in a non-covalentlybonded manner. Application of heat or other perturbations can act toincrease the volume of the non-covalently bonded lofting agent which inturn increases the overall thickness of the prepreg or core, e.g., theprepreg or core thickness increases as the size of the lofting agentincreases and/or additional air becomes trapped in the prepreg. Forexample, the lofting agent can be operative as a heat-sensitive agentsuch that application of a suitable stimulus, e.g., radiant heat,functions to increase the overall thickness of the prepreg. In someinstances, the lofting agent can be configured as a binary lofting agentwhich can expand from no loft to full loft after application of astimulus such as heat. In additional configurations, the lofting agentcan be a linear lofting agent whose size increases substantiallylinearly with increasing temperature until the lofting agent reachesfull loft. In other instances, the lofting agent can be a step-wiselofting agent, e.g., a step-wise lofting agent in the form ofmicrospheres. As used herein, step-wise lofting or a step-wise loftingagent refers to a lofting agent whose thickness increases withtemperature, then plateaus, then increases again with increasingtemperature. The step-wise increase in volume provides for enhancedcontrol of overall prepreg thickness and reduces the likelihood ofover-loft. A desired thickness using a prepreg comprising a loftingagent can be achieved by selecting a suitable processing temperature. Ifthe thickness is not sufficient, in many instances, a higher temperaturecan then be applied to increase overall thickness to a desiredthickness.

In certain embodiments, the thermoplastic material of the prepregs orcores described herein may comprise, at least in part, one or more ofpolyethylene, polypropylene, polystyrene, acrylonitrylstyrene,butadiene, polyethyleneterephthalate, polybutyleneterephthalate,polybutylenetetrachlorate, and polyvinyl chloride, both plasticized andunplasticized, and blends of these materials with each other or otherpolymeric materials. Other suitable thermoplastics include, but are notlimited to, polyarylene ethers, polycarbonates, polyestercarbonates,thermoplastic polyesters, polyimides, polyetherimides, polyamides,acrylonitrile-butylacrylate-styrene polymers, amorphous nylon,polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone,polyether sulfone, liquid crystalline polymers, poly(1,4 phenylene)compounds commercially known as PARMAX®, high heat polycarbonate such asBayer's APEC® PC, high temperature nylon, and silicones, as well asalloys and blends of these materials with each other or other polymericmaterials. The thermoplastic material used to form the prepreg can beused in powder form, resin form, rosin form, fiber form or othersuitable forms. Illustrative thermoplastic materials in various formsare described herein and are also described, for example in U.S.Publication Nos. 20130244528 and US20120065283. The exact amount ofthermoplastic material present in the prepreg can vary and illustrativeamounts range from about 20% by weight to about 90% by weight. As notedherein, to increase the overall impact resistance, it may be desirableto configure the prepreg with a thermoplastic polymer with a weightpercent of 50% or more, e.g., 55-80 weight percent, 60-80 weightpercent, etc.

In certain examples, the reinforcing materials of the prepregs may takethe form of fibers which are dispersed throughout the prepreg. Forexample, one or more of glass fibers, carbon fibers, graphite fibers,synthetic organic fibers, particularly high modulus organic fibers suchas, for example, para- and meta-aramid fibers, nylon fibers, polyesterfibers, or any of the high melt flow index resins described herein thatare suitable for use as fibers, natural fibers such as hemp, sisal,jute, flax, coir, kenaf and cellulosic fibers, mineral fibers such asbasalt, mineral wool (e.g., rock or slag wool), wollastonite, aluminasilica, and the like, or mixtures thereof, metal fibers, metalizednatural and/or synthetic fibers, ceramic fibers, yarn fibers, ormixtures thereof may be present in the prepreg. In some embodiments, anyof the aforementioned fibers can be chemically treated prior to use toprovide desired functional groups or to impart other physical propertiesto the fibers, e.g., may be chemically treated so that they can reactwith the thermoplastic material, the lofting agent or both. In someinstances, the fibers used in the prepreg can first be reacted with thelofting agent to provide a derivatized fiber that is then mixed with thethermoplastic material. Alternatively, the lofting agent can be reactedwith the thermoplastic material of the prepreg to provide a derivatizedthermoplastic material that is then mixed with the fibers. The fibercontent in the prepreg may be from about 20% to about 90% by weight ofthe prepreg, more particularly from about 30% to about 70%, by weight ofthe prepreg. Typically, the fiber content of a composite articlecomprising the prepreg varies between about 20% to about 90% by weight,more particularly about 30% by weight to about 80% by weight, e.g.,about 40% to about 70% by weight of the composite. As noted herein, toincrease the overall impact resistance of the prepreg, it may bedesirable to include less fibers by weight than thermoplastic polymer byweight. For example, in some instances the amount of reinforcingmaterials or fibers present in the prepreg or core layer may be below 50weight percent, more particularly below 45 weight percent, e.g., below40 weight percent or below 30 weight percent. The particular size and/ororientation of the fibers used may depend, at least in part, on thepolymer material used and/or the desired properties of the resultingprepreg. Suitable additional types of fibers, fiber sizes and amountswill be readily selected by the person of ordinary skill in the art,given the benefit of this disclosure. In one non-limiting illustration,fibers dispersed within a thermoplastic material and lofting agent toprovide a prepreg generally have a diameter of greater than about 5microns, more particularly from about 5 microns to about 22 microns, anda length of from about 5 mm to about 200 mm; more particularly, thefiber diameter may be from about 5 microns to about 22 microns and thefiber length may be from about 5 mm to about 75 mm.

The exact type of lofting agent used in the prepreg can depend onnumerous factors including, for example, the desired loftingtemperature, the desired degree of loft, etc. In some instances,microsphere lofting agents which can increase their size upon exposureto convection heating may be used. Illustrative commercially availablelofting agents are available from Kureha Corp. In some instances, thelofting agent is present in microsphere form and may comprise an averageparticle size of at least 40 microns, for example. In other instances, afirst lofting agent with a first average particle size and a secondlofting agent with a second average particle size, different from thefirst average particle size, may be used.

In some configurations, the prepreg of the underbody shield may be asubstantially halogen free or halogen free prepreg to meet therestrictions on hazardous substances requirements for certainapplications. In other instances, the prepreg may comprise a halogenatedflame retardant agent such as, for example, a halogenated flameretardant that comprises one of more of F, Cl, Br, I, and At orcompounds that including such halogens, e.g., tetrabromo bisphenol-Apolycarbonate or monohalo-, dihalo-, trihalo- ortetrahalo-polycarbonates. In some instances, the thermoplastic materialused in the prepregs and cores may comprise one or more halogens toimpart some flame retardancy without the addition of another flameretardant agent. Where halogenated flame retardants are present, theflame retardant is desirably present in a flame retardant amount, whichcan vary depending on the other components which are present. Forexample, the halogenated flame retardant may be present in about 0.1weight percent to about 15 weight percent (based on the weight of theprepreg), more particularly about 1 weight percent to about 13 weightpercent, e.g., about 5 weight percent to about 13 weight percent. Ifdesired, two different halogenated flame retardants may be added to theprepregs. In other instances, a non-halogenated flame retardant agentsuch as, for example, a flame retardant agent comprising one or more ofN, P, As, Sb, Bi, S, Se, and Te can be added. In some embodiments, thenon-halogenated flame retardant may comprise a phosphorated material sothe prepregs may be more environmentally friendly. Where non-halogenatedor substantially halogen free flame retardants are present, the flameretardant is desirably present in a flame retardant amount, which canvary depending on the other components which are present. For example,the substantially halogen free flame retardant may be present in about0.1 weight percent to about 15 weight percent (based on the weight ofthe prepreg), more particularly about 1 weight percent to about 13weight percent, e.g., about 5 weight percent to about 13 weight percentbased on the weight of the prepreg. If desired, two differentsubstantially halogen free flame retardants may be added to theprepregs. In certain instances, the prepregs described herein maycomprise one or more halogenated flame retardants in combination withone or more substantially halogen free flame retardants. Where twodifferent flame retardants are present, the combination of the two flameretardants may be present in a flame retardant amount, which can varydepending on the other components which are present. For example, thetotal weight of flame retardants present may be about 0.1 weight percentto about 20 weight percent (based on the weight of the prepreg), moreparticularly about 1 weight percent to about 15 weight percent, e.g.,about 2 weight percent to about 14 weight percent based on the weight ofthe prepreg. The flame retardant agents used in the prepregs describedherein can be added to the mixture comprising the lofting agent,thermoplastic material and fibers (prior to disposal of the mixture on awire screen or other processing component) or can be added after theprepreg is formed.

In certain configurations, the articles described herein may comprise aporous core. In certain examples, the porous core comprises one or morethermoplastic materials and a plurality of reinforcing materials, e.g.,reinforcing fibers, that can be held in place by the cured thermoplasticmaterial in a web or network structure to provide a plurality of opencells, void space or a web in the core. In some instances, lofting agentcan be present in the void space of the porous core in a manner wherethe lofting agent generally does not covalently bond with thethermoplastic materials and/or the fibers. For example, thethermoplastic materials and/or the fibers can be selected so that theyare generally inert or non-reactive with the lofting agent. Even thoughthe lofting agent may not covalently bond to the thermoplastic materialand/or the fibers, there typically is covalent bonding present in orwithin the lofting agent itself. In other instances, it may be desirableto covalently bond the lofting agent to the thermoplastic materials, thefibers or both to provide some covalently bonded lofting agent in thecore. Even where bonded lofting agent are present in the core, thelofting agent desirably can still increase their occupied volume undersuitable conditions such as, for example, convection heating to permitlofting of the core. In some instances, both covalently bonded loftingagent and non-covalently bonded lofting agent may also be present in thecore. While some configurations of the core may comprise lofting agentwhere about 100% of the lofting agent are non-covalently bonded, weakinteractions such as van der Waals' interactions or electrostaticinteractions can take place between the lofting agent and the othercomponents of the core, e.g., charge-charge interactions or hydrophobicinteractions can take place between the various components present inthe core.

In certain configurations, a core can comprise lofting agent dispersedthroughout the core. In some instances, the lofting agent dispersion canbe substantially homogeneous or substantially uniform from a firstsurface to a second surface of the core. As described in more detailherein, to achieve such substantially homogeneous or substantiallyuniform distribution of lofting agent in the core, the components of thecore can be mixed together to form a dispersion. Mixing can be performeduntil the dispersion comprises a substantially homogeneous orsubstantially uniform mixture of the lofting agent, the thermoplasticmaterials and the fibers in the dispersion. The core may then be formedas described herein, e.g., by disposing the dispersion on a wire screenusing a suitable laying process followed by melting, compressing and/orconsolidation of the thermoplastic material of the core. In otherconfigurations, it may be desirable to provide a gradient distributionof lofting agent from one surface of the core to the other surface ofthe core. In some configurations, a substantially uniform distributionof lofting agent is present in a core and then additional lofting agentis added to one side of the core to provide a gradient distribution.Such additional lofting agent can be added directly to the core, e.g.,by spraying or coating a solution comprising the lofting agent, or canbe added by coupling a skin, additional prepreg or core or othercomponent comprising lofting agent to the core. For example, a firstcore and a second core disposed on the first core can provide acomposite article. Each of the cores may comprise a substantiallyuniform distribution of lofting agent, but the amount and/or type oflofting agent in the two cores can be different, e.g., the loading ratescan be different or the materials themselves may be different. Ifdesired, however, only one of the cores may comprise lofting agent andthe other core may not comprise a lofting agent or may comprise adifferent lofting agent. The thermoplastic materials of the cores can bemelted to provide a single combined core including materials from thetwo cores. The result of melting of the cores is a composite core with agradient distribution of lofting agent. In other configurations, adistribution of lofting agent in a core can be provided by coupling askin or other material comprising lofting agent to the core. In otherinstances, the skin can be melted into the core to couple the skin andthe core to leave a coupled skin/core composite material without anysubstantial interface. If desired and as described in more detail below,an additional skin, which may or may not comprise lofting agent can alsobe coupled to the core on an opposite side from the first skin.

In certain configurations, the thermoplastic material of the core may beused to provide a core in fiber form, particle form, resin form or othersuitable forms. In some examples, the thermoplastic material used in thecore can be present in particle form and have an average particle sizethat is substantially the same as the average particle size of thelofting agent (when present). By matching the particles sizes of thethermoplastic material and the lofting agent, enhanced processing of thecores including, for example, increased retention of the lofting agentin the core, an increase in reserved loft capacity, etc. can beachieved. In some instances, the average particle size of the loftingagent and the average particle size of the thermoplastic material canvary by about 5% to about 10% and enhanced processing can still beachieved. In certain configurations, the average particle size of eachof the thermoplastic material and the lofting agent in the core canrange from about 50 microns to about 900 microns. In other instances,lofting agent with an average particle size about the same as theaverage particle size of the thermoplastic material can be present alongwith lofting agent of an average particle size that is different thanthe average particle size of the thermoplastic material. Even though theaverage particle size of the lofting agent may differ, the chemicalcomposition of the lofting agent can be the same or can be different. Inyet other configurations, two or more thermoplastic materials withdifferent average particle sizes can be present. If desired, two loftingagent with average particle sizes that are substantially the same as theaverage particle sizes of the two thermoplastic materials can be presentin the core. The two lofting agent may be chemically the same or may bechemically distinct. Similarly, the thermoplastic materials can bechemically the same (but have a different average particle size) or canbe chemically distinct.

In certain embodiments, the core generally comprises a substantialamount of open cell structure such that void space is present in thecore. For example, the core layer may comprise a void content orporosity of 0-30%, 10-40%, 20-50%, 30-60%, 40-70%, 50-80%, 60-90%,0-40%, 0-50%, 0-60%, 0-70%, 0-80%, 0-90%, 5-30%, 5-40%, 5-50%, 5-60%,5-70%, 5-80%, 5-90%, 5-95%, 10-50%, 10-60%, 10-70%, 10-80%, 10-90%,10-95%, 20-60%, 20-70%, 20-80%, 20-90%, 20-95%, 30-70%, 30-80%, 30-90%,30-95%, 40-80%, 40-90%, 40-95%, 50-90%, 50-95%, 60-95% 70-80%, 70-90%,70-95%, 80-90%, 80-95% or any illustrative value within these exemplaryranges. In some instances, the core comprises a porosity or void contentof greater than 0%, e.g., is not fully consolidated, up to about 95%.Unless otherwise stated, the reference to the core comprising a certainvoid content or porosity is based on the total volume of the core andnot necessarily the total volume of the core plus any other materials orlayers coupled to the core. Compared to a prepreg, the porosity of thecore can be the same or can be different. For example, in manyinstances, a prepreg is formed into a core by passing a prepreg througha set of rollers or by pressing one or both surfaces of the prepreg. Insuch instances, the porosity of the core may be different than theporosity of the prepreg, e.g., can be lower. In some instances, theporosity of the core is intentionally selected to be less than acomparable prepreg to provide for increased lofting capacity of the coreinto a final formed article or product.

In certain embodiments, the high porosity present in the core permitstrapping of lofting agent within the pores of the core. For example,lofting agent can reside in the void space in a non-covalently bondedmanner. Application of heat or other perturbations can act to increasethe volume of the non-covalently bonded lofting agent which in turnincreases the overall thickness of the core. For example, the loftingagent can be operative as a lofting agent such that application of asuitable stimulus, e.g., convection heat, functions to increase theoverall thickness of the core.

In certain embodiments, the thermoplastic material of the coresdescribed herein may comprise, at least in part, one or more polymersincluding, but not limited to, polyethylene, polypropylene, polystyrene,acrylonitrylstyrene, butadiene, polyethyleneterephthalate,polybutyleneterephthalate, polybutylenetetrachlorate, and polyvinylchloride, both plasticized and unplasticized, and blends of thesematerials with each other or other polymeric materials. Other suitablethermoplastics include, but are not limited to, polyarylene ethers,polycarbonates, polyestercarbonates, thermoplastic polyesters,polyimides, polyetherimides, polyamides,acrylonitrile-butylacrylate-styrene polymers, amorphous nylon,polyarylene ether ketone, polyphenylene sulfide, polyaryl sulfone,polyether sulfone, liquid crystalline polymers, poly(1,4 phenylene)compounds commercially known as PARMAX®, high heat polycarbonate such asBayer's APEC® PC, high temperature nylon, and silicones, as well asalloys and blends of these materials with each other or other polymericmaterials. The thermoplastic material used to form the core can be usedin powder form, resin form, rosin form, fiber form or other suitableforms. Illustrative thermoplastic materials in various forms aredescribed herein and are also described, for example in U.S. PublicationNos. 20130244528 and US20120065283. The exact amount of thermoplasticmaterial present in the core can vary and illustrative amounts rangefrom about 20% by weight to about 90% by weight. To increase the overallimpact resistance, it may be desirable to configure the core with athermoplastic polymer with a weight percent of 50% or more, e.g., 55-80weight percent, 60-80 weight percent, etc. In some embodiments, thethermoplastic polymer component of the core is the “major” component ofthe core in that it is the material present in the highest weightpercentage of the core.

In certain examples, the reinforcing materials of the cores may take theform of fibers that can comprise glass fibers, carbon fibers, graphitefibers, synthetic organic fibers, particularly high modulus organicfibers such as, for example, para- and meta-aramid fibers, nylon fibers,polyester fibers, or any of the high melt flow index resins describedherein that are suitable for use as fibers, natural fibers such as hemp,sisal, jute, flax, coir, kenaf and cellulosic fibers, mineral fiberssuch as basalt, mineral wool (e.g., rock or slag wool), wollastonite,alumina silica, and the like, or mixtures thereof, metal fibers,metalized natural and/or synthetic fibers, ceramic fibers, yarn fibers,or mixtures thereof. In some embodiments, any of the aforementionedfibers can be chemically treated prior to use to provide desiredfunctional groups or to impart other physical properties to the fibers,e.g., may be chemically treated so that they can react with thethermoplastic material, the lofting agent or both. In some instances,the fibers used in the core can first be reacted with the lofting agentto provide a derivatized fiber that is then mixed with the thermoplasticmaterial. Alternatively, the lofting agent may be reacted with thethermoplastic material of the core to provide a derivatizedthermoplastic material that is then mixed with the fibers. The fibercontent in the core may be from about 20% to about 90% by weight of thecore, more particularly from about 30% to about 70%, by weight of thecore. The particular size and/or orientation of the fibers used maydepend, at least in part, on the polymer material used and/or thedesired properties of the resulting core. Suitable additional types offibers, fiber sizes and amounts will be readily selected by the personof ordinary skill in the art, given the benefit of this disclosure. Inone non-limiting illustration, fibers dispersed within a thermoplasticmaterial and lofting agent to provide a core generally have a diameterof greater than about 5 microns, more particularly from about 5 micronsto about 22 microns, and a length of from about 5 mm to about 200 mm;more particularly, the fiber diameter may be from about microns to about22 microns and the fiber length may be from about 5 mm to about 75 mm.

In some instances, the core may be a substantially halogen free orhalogen free core to meet the restrictions on hazardous substancesrequirements for certain applications. In other instances, the core maycomprise a halogenated flame retardant agent such as, for example, ahalogenated flame retardant that comprises one of more of F, Cl, Br, I,and At or compounds that including such halogens, e.g., tetrabromobisphenol-A polycarbonate or monohalo-, dihalo-, trihalo- ortetrahalo-polycarbonates. In some instances, the thermoplastic materialused in the cores may comprise one or more halogens to impart some flameretardancy without the addition of another flame retardant agent. Wherehalogenated flame retardants are present, the flame retardant isdesirably present in a flame retardant amount, which can vary dependingon the other components which are present. For example, the halogenatedflame retardant may be present in about 0.1 weight percent to about 15weight percent (based on the weight of the core), more particularlyabout 1 weight percent to about 13 weight percent, e.g., about 5 weightpercent to about 13 weight percent. If desired, two differenthalogenated flame retardants may be added to the core. In otherinstances, a non-halogenated flame retardant agent such as, for example,a flame retardant agent comprising one or more of N, P, As, Sb, Bi, S,Se, and Te can be added. In some embodiments, the non-halogenated flameretardant may comprise a phosphorated material so the cores may be moreenvironmentally friendly. Where non-halogenated or substantially halogenfree flame retardants are present, the flame retardant is desirablypresent in a flame retardant amount, which can vary depending on theother components which are present. For example, the substantiallyhalogen free flame retardant may be present in about 0.1 weight percentto about 15 weight percent (based on the weight of the core), moreparticularly about 1 weight percent to about 13 weight percent, e.g.,about 5 weight percent to about 13 weight percent based on the weight ofthe cores. If desired, two different substantially halogen free flameretardants may be added to the cores. In certain instances, the prepregsand cores described herein may comprise one or more halogenated flameretardants in combination with one or more substantially halogen freeflame retardants. Where two different flame retardants are present, thecombination of the two flame retardants may be present in a flameretardant amount, which can vary depending on the other components whichare present. For example, the total weight of flame retardants presentmay be about 0.1 weight percent to about 20 weight percent (based on theweight of the core), more particularly about 1 weight percent to about15 weight percent, e.g., about 2 weight percent to about 14 weightpercent based on the weight of the core. The flame retardant agents usedin the cores described herein can be added to the mixture comprising thelofting agent materials, thermoplastic material and fibers (prior todisposal of the mixture on a wire screen or other processing component)or can be added after the prepreg is formed or the core is cured, e.g.,by soaking the prepreg or core in the flame retardant agent or sprayingflame retardant agent on the prepreg or core.

In certain embodiments, as noted herein, the composite articles maycomprise a skin material disposed on a surface of the prepreg or core toprovide an underbody shield composition that can be processed into anunderbody shield. Referring to FIG. 9, an article 900 comprises aprepreg or core 910 that comprises a thermoplastic polymer material, aplurality of reinforcing fibers and lofting agent disposed in the voidspace of the prepreg or core. The article 900 comprises a first film 920disposed on the prepreg or core 910. The film comprises suitableproperties to increase impact resistance. For example, the film 920 maybe comprised of a homopolymer such as a polyolefin (optionally with oneor more additives) that provides impact resistance. Illustrativehomopolymers for the film 920, include but are not limited to,polyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate homopolymers. Where acopolymer is present in the film 920, the copolymers may be produced,for example, using one or more of polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate. The exact thickness of the film can vary and in someinstances the film is desirably thick enough to provide at least 50impacts under the SAE J400 protocol. The film thickness can vary, forexample, based on the thickness and properties of the core layer. Insome embodiments, the film 920 is at least about 10 mils thick, moreparticularly, 12 mils, thick, 14 mils thick, 16 mils thick, 18 milsthick or 20 mils thick. The exact weight percentages of thermoplasticpolymer in the core 910 can also vary, the thermoplastic polymer istypically present at a larger weight percentage than the reinforcingfibers and the lofting agent, e.g., the thermoplastic polymer may bepresent at 50-55 weight percent or more in the core 910. In someinstances, the thermoplastic polymer of the core 910 may comprisepolypropylene, the reinforcing fibers of the core 910 may be glassfibers, the lofting agent of the core may comprise microspheres and theskin layer 920 may be (or may comprise) a polypropylene homopolymerfilm.

In certain configurations, the prepregs and cores described herein canbe used to provide an article comprising a skin on each side of theprepreg or core. Referring to FIG. 10, an article 1000 is showncomprising a prepreg or core 1010, an impact resistant film 1020disposed on a first surface of the prepreg or core 1010 and a scrim 1030disposed on a second surface of the prepreg or core 1010. The prepreg orcore 1010 may comprise any of the materials described herein inconnection with prepregs and cores, e.g., a thermoplastic material,reinforcing fibers and a lofting agent dispersed in the prepreg or core1010. In some instances, a thermoplastic polymer comprises a majorcomponent of the prepreg or core 1010, e.g., is present at 50 weightpercent or more in the prepreg or core. The film 1020 may be comprisedof a homopolymer such as a polyolefin (optionally with one or moreadditives) that provides impact resistance. Illustrative homopolymersfor the film 1020, include but are not limited to, polyethylene,polypropylene, polyamide, polyethylene terephthalate, polycarbonate andpolymethyl methacrylate homopolymers. Where a copolymer is present inthe film 1020, the copolymers may be produced, for example, using one ormore of polyethylene, polypropylene, polyamide, polyethyleneterephthalate, polycarbonate and polymethyl methacrylate. The scrim 1030may be a fiber based scrim and may comprise at least one of glassfibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineralfibers, metal fibers, metalized synthetic fibers, and metalizedinorganic fibers. In some configurations of the article 1000, the core1010 comprises polypropylene, glass fibers and a microsphere loftingagent, the film 1020 is a polypropylene homopolymer film and the scrimis a polyester non-woven.

In certain instances, an underbody shield can comprise a prepreg orcore, at least one film disposed on the prepreg or core, a scrimdisposed on the prepreg or core and a decorative or cover layer disposedon the scrim. Referring to FIG. 11, an article such as an underbodyshield 1100 is shown comprising a prepreg or core 1110, a film 1120disposed on a first surface of the prepreg or core 1110, a scrim 1030disposed on a second surface of the prepreg or corer 1110 and adecorative layer 1140 disposed on the scrim 1130. The prepreg or core1110 may comprise any of the materials described herein in connectionwith prepregs and cores, e.g., a thermoplastic material, reinforcingfibers and a lofting agent dispersed in the prepreg or core 1110. Insome embodiments, the core 1110 comprises a thermoplastic polymermaterial as a major component. The film 1120 may be comprised of ahomopolymer such as a polyolefin (optionally with one or more additives)that provides impact resistance. Illustrative homopolymers for the film1120, include but are not limited to, polyethylene, polypropylene,polyamide, polyethylene terephthalate, polycarbonate and polymethylmethacrylate homopolymers. Where a copolymer is present in the film1120, the copolymers may be produced, for example, using one or more ofpolyethylene, polypropylene, polyamide, polyethylene terephthalate,polycarbonate and polymethyl methacrylate. The scrim 1130 may be a fiberbased scrim (or other scrims) and may comprise at least one of glassfibers, aramid fibers, graphite fibers, carbon fibers, inorganic mineralfibers, metal fibers, metalized synthetic fibers, and metalizedinorganic fibers. In some configurations of the article 1100, the core1110 comprises polypropylene, glass fibers and a microsphere loftingagent, the film 1120 is a polypropylene homopolymer film, the scrim 1130is a polyester non-woven and the decorative layer 1140 may be formed,e.g., from a thermoplastic film of polyvinyl chloride, polyolefins,thermoplastic polyesters, thermoplastic elastomers, or the like. Thedecorative layer 1140 may also be a multi-layered structure thatincludes a foam core formed from, e.g., polypropylene, polyethylene,polyvinyl chloride, polyurethane, and the like. A fabric may be bondedto the foam core, such as woven fabrics made from natural and syntheticfibers, organic fiber non-woven fabric after needle punching or thelike, raised fabric, knitted goods, flocked fabric, or other suchmaterials. The fabric may also be bonded to the foam core with athermoplastic adhesive, including pressure sensitive adhesives and hotmelt adhesives, such as polyamides, modified polyolefins, urethanes andpolyolefins. The decorative layer 1140 may also be produced usingspunbond, thermal bonded, spun lace, melt-blown, wet-laid, and/ordry-laid processes.

In certain embodiments, while the specific configurations shown in FIGS.9-11 are described in reference to the various components being presentas a single component, the cores, films, scrims, etc. may instead bepresent as a multi-layer assembly if desired. In some configurations,the film may desirably be present as a single layer to avoiddelamination or peeling between film layers. Further, after processingof the various layers in the article, a discernible interface may not bepresent to distinguish one layer from another.

In some embodiments, the prepregs and cores may include additionalmaterials or additives to impart desired physical or chemicalproperties. For example, one or more dyes, texturizing agents,colorants, viscosity modifiers, smoke suppressants, synergisticmaterials, lofting agents, particles, powders, biocidal agents, foams orother materials can be mixed with or added to the prepregs or the cores.In some instances, the prepregs or cores may comprise one or more smokesuppressant compositions in the amount of about 0.2 weight percent toabout 10 weight percent. Illustrative smoke suppressant compositionsinclude, but are not limited to, stannates, zinc borates, zincmolybdate, magnesium silicates, calcium zinc molybdate, calciumsilicates, calcium hydroxides, and mixtures thereof. If desired, asynergist material can be present to enhance the physical properties ofthe prepregs or cores. If desired, a synergist material that enhanceslofting ability may be present. Illustrative synergist materialsinclude, but are not limited to, sodium trichlorobenzene sulfonatepotassium, diphenyl sulfone-3-sulfonate, and mixtures thereof.

In other instances, the prepregs or cores described herein may comprisea thermosetting material in a desired amount, e.g., in a minor amountless than about 50 weight percent based on the total weight of theprepreg or core, to impart desired properties to the core. Thethermosetting material may be mixed with the thermoplastic material ormay be added as a coating on one or more surfaces of the prepregs orcores.

In certain embodiments, the prepregs or cores described herein can beconfigured as (or used in) a glass mat thermoplastic composite (GMT) ora light weight reinforced thermoplastic (LWRT). One such LWRT isprepared by HANWHA AZDEL, Inc. and sold under the trademark SUPERLITE®mat. SUPERLITE® mat loaded with lofting agent can provide desirableattributed including, for example, flame retardancy and enhancedprocessing capabilities. The areal density of such a GMT or LWRT canrange from about 400 grams per square meter (gsm) of the GMT or LWRT toabout 4000 gsm, although the areal density may be less than 400 gsm orgreater than 4000 gsm depending on the specific application needs. Insome embodiments, the upper density can be less than about 4000 gsm. Incertain instances, the GMT or the LWRT may comprise lofting agentmaterial disposed in void space of the GMT or the LWRT. For example,non-covalently bonded lofting agent can be present in void space of theGMT or the LWRT. In other instances, covalently-bonded lofting agent canbe present in void space of the GMT or the LWRT. In yet otherconfigurations, both non-covalently bonded lofting agent and covalentlybonded lofting agent can be present in the GMT or the LWRT. In certainconfigurations where a GMT or LWRT prepreg or core is used incombination with lofting agent, the basis weight of the GMT or LWRT canbe reduced to less than 800 gsm, 600 gsm or 400 gsm, for example, whilestill providing suitable performance properties, e.g., suitable peelstrength between the LWRT and any skin disposed thereon. If desired, anadditional lofting agent, e.g., microspheres can be present in the GMTor LWRT. In some instances, the basis weight of the LWRT used as a coreof the underbody shield may be less than about 1500 gsm, e.g., 1400 gsm,1350 gsm, 1300 gsm, 1275 gsm, 1250 gsm, 1225 gsm or 1200 gsm, and maycomprise polypropylene, glass fibers and microspheres as a loftingagent. Where the basis weight of the LWRT is less than 1500 gsm, thepolypropylene component may be present in a major amount, e.g., 50weight percent or more.

In producing the prepregs and cores described herein, it may bedesirable to use a wet-laid process. For example, a liquid or fluidmedium comprising dispersed material, e.g., thermoplastic materials,fibers and lofting agent material optionally with any one or moreadditives described herein (e.g., other lofting agents or flameretardant agents), may be stirred or agitated in the presence of a gas,e.g., air or other gas. The dispersion may then be laid onto a support,e.g., a wire screen or other support material. The stirred dispersionmay comprise one or more active agents, e.g., anionic, cationic, ornon-ionic such as, for example, those sold under the name ACE liquid byIndustrial Soaps Ltd., that sold as TEXOFOR® FN 15 material, by GloverChemicals Ltd., and those sold as AMINE Fb 19 material by Float-Ore Ltd.These agents can assist in dispersal of air in the liquid dispersion.The components can be added to a mixing tank, flotation cell or othersuitable devices in the presence of air to provide the dispersion. Whilean aqueous dispersion is desirably used, one or more non-aqueous fluidsmay also be present to assist in dispersion, alter the viscosity of thefluid or otherwise impart a desired physical or chemical property to thedispersion or the prepreg, core or article. In some examples, to impartenhanced impact resistance to the core, the amount of thermoplasticpolymer present in the mixture may exceed the amount of reinforcingfibers and/or lofting agent present in the mixture.

In certain instances, after the dispersion has been mixed for asufficient period, the fluid with the suspended materials can bedisposed onto a screen, moving wire or other suitable support structureto provide a web of laid down material. Suction or reduced pressure maybe provided to the web to remove any liquid from laid down material toleave behind the thermoplastic material, lofting agent and any othermaterials that are present, e.g., fibers, additives, etc. The resultingweb can be dried, consolidated, pressed, lofted, laminated, sized orotherwise processed further to provide a desired prepreg, core orarticle. In some instances, an additive or additional lofting agentmaterial can be added to the web prior to drying, consolidation,pressing, lofting, laminating, sizing or other further processing toprovide a desired prepreg, core or article. In other instances, thelofting agent may be added to the web subsequent to drying,consolidation, pressing, lofting, laminating, sizing or other furtherprocessing to provide a desired prepreg, core or article. While wet laidprocesses may be used, depending on the nature of the thermoplasticmaterial, the lofting agent material and other materials present, it maybe desirable to instead use an air laid process, a dry blend process, acarding and needle process, or other known process that are employed formaking non-woven products. In some instances, additional lofting agentmaterial can be sprayed onto the surface of the prepreg or core afterthe prepreg or core has hardened to some degree by passing the boardunderneath a plurality of coating jets that are configured to spray thelofting agent material at about a ninety degree angle to the prepreg orcore surface.

In some configurations, the prepregs and cores described herein can beproduced by combining a thermoplastic material, fibers, and microspherelofting agent in the presence of a surfactant in an aqueous solution orfoam. The combined components can be mixed or agitated for a sufficienttime to disperse the various materials and provide a substantiallyhomogeneous aqueous mixture of the materials. The dispersed mixture isthen laid down on any suitable support structure, for example, a wiremesh or other mesh or support having a desired porosity. Water can thenbe evacuated through the wire mesh forming a web. The web is dried andheated above the softening temperature of the thermoplastic powder. Theweb is then cooled and pressed to a predetermined thickness to produce acomposite sheet having a void content of between about 1 percent toabout 95 percent. In an alternate embodiment, the aqueous foam alsoincludes a binder material. In some configurations, after the web isheated above the softening temperature of the thermoplastic powder, anadhesive layer comprising a thermoplastic polymer and a thermosettingmaterial can then be disposed on the web.

In certain examples, a prepreg or core in the form of a GMT can beproduced. In certain instances, the GMT can be generally prepared usingchopped glass fibers, a thermoplastic material, lofting agent and anoptional thermoplastic polymer film or films and/or woven or non-wovenfabrics made with glass fibers or thermoplastic resin fibers such as,for example, polypropylene (PP), polybutylene terephthalate (PBT),polyethylene terephthalate (PET), polycarbonate (PC), a blend of PC/PBT,or a blend of PC/PET. In some embodiments, a PP, a PBT, a PET, a PC/PETblend or a PC/PBT blend can be used as a resin. To produce the glassmat, a thermoplastic material, reinforcing materials, lofting agentand/or other additives can be added or metered into a dispersing foamcontained in an open top mixing tank fitted with an impeller. Withoutwishing to be bound by any particular theory, the presence of trappedpockets of air of the foam can assist in dispersing the glass fibers,the thermoplastic material and the lofting agent. In some examples, thedispersed mixture of glass and resin can be pumped to a head-box locatedabove a wire section of a paper machine via a distribution manifold. Thefoam, not the glass fiber, lofting agent or thermoplastic, can then beremoved as the dispersed mixture is provided to a moving wire screenusing a vacuum, continuously producing a uniform, fibrous wet web. Thewet web can be passed through a dryer at a suitable temperature toreduce moisture content and to melt or soften the thermoplasticmaterial. When the hot web exits the dryer, a surface layer such as, forexample, a film and/or scrim may be laid onto the web. In certaininstances, an impact resistant film may be coupled to the web bypressing the film against the web using rollers or other devices. Forexample, after the web is formed, a film may be added to an underside ofthe web and the combined construct can be passed between a set ofrollers to couple the film to the web. In other instances, a scrim maybe added to the top of the web to couple the scrim to the web. The scrimmay be added before, after or simultaneously with the film. For example,a film can be disposed on the web from below and a scrim can be disposedon the web from above. The 3-layered assembly may be passed through aset of nip rollers with selected spacing to press the film and scrimonto the surfaces of the web. For example, the 3-layer assembly may bepassed through the nip of a set of heated rollers. If desired,additional layers such as, for example, a non-woven and/or woven fabriclayer or skin layer may also be attached to one side or to both sides ofthe web to facilitate ease of handling the glass fiber-reinforced mat.The composite can then be passed through tension rolls and continuouslycut (guillotined) into the desired size for later forming into an endproduct article. Further information concerning the preparation of suchGMT composites, including suitable materials and processing conditionsused in forming such composites, are described, for example, in U.S.Pat. Nos. 6,923,494, 4,978,489, 4,944,843, 4,964,935, 4,734,321,5,053,449, 4,925,615, 5,609,966 and U.S. Patent Application PublicationNos. US 2005/0082881, US2005/0228108, US 2005/0217932, US 2005/0215698,US 2005/0164023, and US 2005/0161865.

In some instances, a prepreg, core or article can be produced bycombining a thermoplastic material, reinforcing fibers and lofting agentin a mixture to form an agitated aqueous foam. The agitated aqueous foamcan be disposed onto a wire support. Water can be evacuated to form aweb or open cell structure. The web can be heated, e.g., usingconvection heating, above the melting temperature of the thermoplasticmaterial under conditions such that substantially no loft occurs. Ifdesired, pressure can be applied to the web to provide a thermoplasticcomposite sheet comprising the lofting agent. The sheet can be furtherprocessed by selecting suitable heating conditions to provide a desiredloft. A skin or cover layer can then be disposed on the adhesive layer.In some instances, heating conditions that are effective to loft thesheet can be applied to increase the overall board thickness. Forexample, the multi-layer assembly can be placed in a mold and heatingconditions can be applied to loft the sheet to press the surfaces of thesheet against the other layers of the assembly while still providing adesired peel strength. In other instances, one or more areas of themulti-layer assembly can be drawn to a desired depth to form structureswith a selected geometry and/or dimensions.

In certain instances, a method of producing a composite articlecomprises combining a thermoplastic material, reinforcing fibers and alofting agent in a mixture to form an agitated aqueous foam. The foam isdisposed onto a wire support, and the water is evacuated to form a webor open cell structure comprising the thermoplastic material, fibers andlofting agent materials. In some instances, the web is then heated to afirst temperature above the melting temperature of the thermoplasticmaterial, in which the first temperature is below a loft onsettemperature of the lofting agent so substantially no loft occurs. Inother instances, the web can be heating using heating conditions thatmelt the thermoplastic material, e.g., convection heating, but do notsubstantially loft the lofting agent. If desired, pressure can then beapplied to the web, e.g., using nip rollers or other devices, to providea thermoplastic composite sheet comprising the lofting agent dispersedin the web.

In certain instances, an impact resistant film may be coupled to an LWRTweb by pressing the film against the web using rollers or other devices.For example, after the web is formed, a film may be added to anunderside of the web and the combined construct can be passed between aset of rollers to couple the film to the web. In other instances, ascrim may be added to the top of the web to couple the scrim to the web.The scrim may be added before, after or simultaneously with the film.For example, a film can be disposed on the web from below and a scrimcan be disposed on the web from above. The 3-layered assembly may bepassed through a set of nip rollers with selected spacing to press thefilm and scrim onto the surfaces of the web.

Certain examples are described below to illustrate better some of thenovel aspects and configurations described herein.

Example 1

Several examples below refer to testing using a gravelometer test. Inthe test procedure, sample plaques of 100 mm×300 mm are placed in aholder with the back side supported against a steel plate. Stones wereprojected at the plaques at 90 degrees or perpendicular to the surface.The stones used were water eroded alluvial road gravel 8 to 16 mm insize. Stones were fed through the air stream with an 8±2 secondsinterval at an air pressure of 70 psi. Every 10 cycles the specimen wastaken out for observation. Any cracking, blistering, delamination, orerosion though the outer surface indicates failure. The test wascontinued until any of the above mentioned failure was observed. Twospecimens were tested for each sample; the cycles at failure were theaverage of two specimens. The basis weight of the tested plaques wasabout 1250 grams per square meter (gsm). The tested plaques included ascrim (0.1-0.2 mm thick), a film (50-500 microns thick) and apolypropylene resin/glass fiber core between them to provide an overallthickness of about 2 mm.

Example 2

The tested LWRT consisted of two primary components: chopped glass fiberand polypropylene (PP) resin. The glass fiber acts as the high modulusreinforcement and the PP resin is the matrix, which holds thereinforcement in place and deforms to distribute the stress to thereinforcement under applied load. By changing the charging speed of thetwo major components, the glass fiber/PP resin ratio in the finalproduct can be altered. The effect of glass/resin ratio on thegravelometer performance of the LWRT is shown in Table 1.

TABLE 1 Gravelometer Test (cycles) Peel Spec- Spec- Average StrengthEffect of Glass Content imen 1 imen 2 (cycles) (N/cm) High Resin ContentSample 70 75 73 12.9 (55 wt % PP resin) Low Resin Content Sample 40 4040 4.6 (45 wt % PP resin)The gravelometer performance of the LWRT improves with increased resincontent (or decreased glass content). The gravelometer failure cyclesalmost doubled by increasing the PP resin content to 55 weight percent.A couple of factors could be contributing to the increased gravelometerperformance with increasing PP resin content. First, the higher resincontent increases the “softness” of the core. This will enable largerelastic deformation of the core under impact and helps absorb the impactenergy. Secondly, the higher resin content can improve the bondingstrength between the skin film and the composite core. The loweradhesion strength will lead to the earlier delamination of the skin filmfrom the core which causes the cover film to fail faster. Therefore, thehigh resin content sample could undergo much more gravel impact cyclesthan the low resin content sample.

Example 3

An LWRT product that incorporated a PP homopolymer film onto the corematerial was tested. This skin film provides the moisture resistance,salt spray resistance and stone chipping resistance to the compositestructure. In the stone impingement test, when the skin film delaminatedfrom the core or shows cracking in the film, the underbody panel isconsidered to have failed the gravelometer test. Films of the samecomposition but different thicknesses were tested in this study toinvestigate the effect of skin film thickness on the stone impingementperformance of the UBS panel. Table 2 shows the gravelometer test resultof the molded LWRT sheets with different thickness skin films.

TABLE 2 Gravelometer Test Effect of Film Film Thickness (cycles) AverageThickness (mil) 1 2 (cycles) Sample 1 12 60 55 58 Sample 2 8 25 35 30Sample 3 5 10 25 18The results are consistent with the film thickness effecting stoneimpingement resistance. When the film thickness increased from 5 mils to12 mils, the number of cycles until failure (using the gravelometertest) increased by more than two times. Although the thinner filmusually has better adhesion to the core material, the film itself wasnot able to sustain the stone impact and could be broken much moreeasily than the thicker film.

Example 4

The effect of the melt flow index (MFI) of the resin of the core wasmeasured to determine if changes to the MFI of the core resin alteredthe impact performance. MFI may be measured, for example, using ASTMD1238, condition L dated 2013 and may be expressed, for example, in g/10min. although the units are typically omitted. The resin MFI can affecthow fast the resin will be able to flow during the drying process in theoven and how well it can wet-out the glass fiber. The better wet-outusually gives the composite better mechanical strength. Two differentMFI PP resins were tested: the high MFI resin had a MFI value, e.g.,about 300, of about three times of the low MFI resin, e.g., about 100.The comparison of their gravelometer test results are shown in Table 3.

TABLE 3 Gravelometer Test (cycles) Average Effect of Resin MFI 1 2(cycles) Low MFI Sample 40 50 45 High MFI Sample 45 55 50The results are consistent with a higher MFI resin, e.g., 300 or more,providing slightly higher stone impingement performance. Although thehigh MFI resin will help improve the wet-out of the glass fiber duringthe drying process, it did not seem to have a large effect on thegravelometer performance.

Example 5

The effect of a lofting agent on impact resistance was tested. A loftingagent can be added to the LWRT formulation to increase its loftcapability, reducing the weight and improving the acousticalperformance. The effect of the addition of lofting agent is shown inTable 4. HS1100 microsphere lofting agent was used.

TABLE 4 Gravelometer Test (cycles) Average Failure Effect of Loft Agent1 2 (cycles) Sample without lofting agent 60 50 55 Sample with loftingagent 70 75 73The results are consistent with the addition of the lofting agentimproving the stone impingement performance. A 30% increase was observedfor the gravelometer failure cycles with the addition of thismicrosphere lofting agent. This lofting agent expands to a hollow spheretype of structure in the molding process. This foaming peanut type ofstructure appears to contribute to an improvement in the gravelometerperformance.

Example 6

An underbody shield can be produced by disposing a polypropylenehomopolymer film on a LWRT core board comprising about 55 weight percentor more thermoplastic polymer, glass fibers and a lofting agent. Anon-woven scrim may be coupled to an opposite side of the board. Theresulting composite can be further processed by thermoforming to adesired shape and/or size for use as an underbody shield.

Example 7

An underbody shield can be produced by disposing apolypropylene-polyethylene copolymer film (with more than 50% of thecopolymer being polypropylene) on a LWRT core board comprising about 55weight percent or more thermoplastic polymer, glass fibers and a loftingagent. A non-woven scrim may be coupled to an opposite side of theboard. The resulting composite can be further processed by thermoformingto a desired shape and/or size for use as an underbody shield.

Example 8

An underbody shield can be produced by disposing a polypropylenehomopolymer film on a LWRT core board comprising about 55-60 weightpercent or more thermoplastic polymer, about 40-45 weight percent glassfibers and about 0.1-5% by weight lofting agent. A non-woven scrim maybe coupled to an opposite side of the board. The resulting composite canbe further processed by thermoforming to a desired shape and/or size foruse as an underbody shield.

Example 9

An underbody shield can be produced by disposing apolypropylene-polyethylene copolymer film (with more than 50% of thecopolymer being polypropylene) on a LWRT core board comprising about55-60 weight percent or more thermoplastic polymer, about 40-45 weightpercent glass fibers and about 0.1-5% by weight lofting agent. Anon-woven scrim may be coupled to an opposite side of the board. Theresulting composite can be further processed by thermoforming to adesired shape and/or size for use as an underbody shield.

Example 10

An underbody shield can be produced by disposing a polypropylenehomopolymer film on a LWRT core board comprising about 55-60 weightpercent or more thermoplastic polymer, about 40-45 weight percent glassfibers and about 0.1-5% by weight microsphere lofting agent. A non-wovenscrim may be coupled to an opposite side of the board. The resultingcomposite can be further processed by thermoforming to a desired shapeand/or size for use as an underbody shield.

Example 11

An underbody shield can be produced by disposing apolypropylene-polyethylene copolymer film (with more than 50% of thecopolymer being polypropylene) on a LWRT core board comprising about55-60 weight percent or more thermoplastic polymer, about 40-45 weightpercent glass fibers and about 0.1-5% by weight microsphere loftingagent. A non-woven scrim may be coupled to an opposite side of theboard. The resulting composite can be further processed by thermoformingto a desired shape and/or size for use as an underbody shield.

Example 12

Two LWRT boards (with two replicates of each board type) were producedthat included the resin:glass ratios shown in Table 5.

TABLE 5 Gravelometer Failure Cycles Resin:Glass Resin Lofting SampleAverage LWRT Ratio MFI Agent 1 Sample 2 (cycles) Standard 45:55 Low No55 50 53 LWRT High 55:45 High Yes 100 100 100 Gravel Resistant LWRT

The Standard LWRT included a 1200 gsm core 45:55 resin:glass content(100 MFI polypropylene and glass fibers). The high gravel resistant LWRTincluded a 1200 gsm XL2 core (included about 2.8% by weight loftingagent with the balance being resin:glass content at a ratio of about55:45 resin:glass (325 MFI polypropylene and glass fibers). Both LWRTboards included a 225 gsm polypropylene film on one surface of the corethe core and 35 gsm PET scrim on an opposite surface of the core. Lowresin MFI refers to an MFI of about 100, and High resin MFI refers to anMFI of about 300 or more. As noted herein, MFI may be measured, forexample, using ASTM D1238, condition L dated 2013.

The film side of each board was subjected to gravelometer cycles untilfailure or 100 cycles total (end of the test). As shown in Table 5, thestandard LWRT board failed after an average of 53 gravelometer cycles.The resistant LWRT board did not fail after the 100 cycles. Theseresults are consistent with selection of the resin:glass ratio and resinMFI to provide a LWRT with higher gravel resistance.

Example 13

Three LWRT boards were produced with the materials shown in Table 6.

TABLE 6 Composition Name 900 gsm core + 4 mm thick 225 gsm EXV2601-0499ST-10499 polypropylene film (modified polypropylene film 1) 900 gsmcore + 4 mm thick 225 gsm EXV2601-0500 ST-10500 polypropylene film(modified polypropylene film 2) 900 gsm core + 4 mm thick 225 gsmpolypropylene ST-10198 film (unmodified film)ST-10499 included a 900 gsm XL2 core (as noted in Example 12) with a 225gsm EXV2601-0499 polypropylene film one on surface of the XL2 core and a35 gsm PET scrim on an opposite surface of the XL2 core. ST-10500included a 900 gsm XL2 core with a 225 gsm EXV2601-0500 polypropylenefilm on one surface of the XL2 core and a 35 gsm PET scrim on anopposite surface of the XL2 core. ST-10198 included a 900 gsm XL2 corewith a 225 gsm polypropylene film on one surface of the XL2 core and a35 gsm PET scrim on an opposite surface of the XL2 core.

The film side of each of the boards in Table 6 was subjected to agravelometer test. Each board was subjected to 100 kg of gravel at a 90degree angle to the film surface after the boards were placed against a⅛ inch steel backing panel. 70 psi of pressure was used. 2 replicates ofeach board were tested for a total of six boards. Photographs of thesample boards after testing are shown in FIGS. 12A-12C. FIG. 12A is aphotograph of the two ST-10198 boards, FIG. 12B is a photograph of thetwo ST-10499 boards, and FIG. 12C is a photograph of the two ST-10500boards. None of the boards exhibited any objectionable degradation,delamination, cracking, blistering, core exposure, weight loss of otherchanges that altered the boards after the gravelometer testing. Theseresults were consistent with the combination of the core and filmsproviding increased impact resistance compared to a standard LWRT board.

When introducing elements of the examples disclosed herein, the articles“a,” “an,” “the” and “said” are intended to mean that there are one ormore of the elements. The terms “comprising,” “including” and “having”are intended to be open-ended and mean that there may be additionalelements other than the listed elements. It will be recognized by theperson of ordinary skill in the art, given the benefit of thisdisclosure, that various components of the examples can be interchangedor substituted with various components in other examples.

Although certain aspects, examples and embodiments have been describedabove, it will be recognized by the person of ordinary skill in the art,given the benefit of this disclosure, that additions, substitutions,modifications, and alterations of the disclosed illustrative aspects,examples and embodiments are possible.

1. An underbody shield composition comprising: a thermoplastic corelayer comprising a web of open celled structures defined by randomcrossing over of reinforcing fibers held together by a thermoplasticpolymer, the thermoplastic core layer further comprising a lofting agenteffective to increase a thickness of the core layer upon exposure toheat to provide a post lofted core layer; a film disposed on a firstsurface of the core layer, in which the post lofted core layer and filmtogether provide an underbody shield article that can withstand at least50 individual impacts according to a SAE J400 protocol without damage tothe film.
 2. The underbody shield composition of claim 1, in which thefilm is a homopolymer or copolymer film.
 3. The underbody shieldcomposition of claim 2, in which the homopolymer is a polyolefin.
 4. Theunderbody shield composition of claim 1, in which the thermoplasticpolymer is present at 50 weight percent or more in the core layer. 5.The underbody shield composition of claim 4, in which the film is atleast 10 mils thick.
 6. The underbody shield composition of claim 5, inwhich the lofting agent is present at 4 percent by weight or more in thecore layer.
 7. The underbody shield composition of claim 6, in which thereinforcing fibers are selected from the group consisting of glassfibers, carbon fibers, graphite fibers, synthetic organic fibers,inorganic fibers, natural fibers, mineral fibers, metal fibers,metalized inorganic fibers, metalized synthetic fibers, ceramic fibers,and combinations thereof.
 8. The underbody shield composition of claim7, in which the thermoplastic polymer is a polymer resin that isselected from the group consisting of a polyolefin resin, athermoplastic polyolefin blend resin, a polyvinyl polymer resin, abutadiene polymer resin, an acrylic polymer resin, a polyamide resin, apolyester resin, a polycarbonate resin, a polyestercarbonate resin, apolystyrene resin, an acrylonitrylstyrene polymer resin, anacrylonitrile-butylacrylate-styrene polymer resin, a polyether imideresin, a polyphenylene ether resin, a polyphenylene oxide resin, apolyphenylenesulphide resin, a polyether resin, a polyetherketone resin,a polyacetal resin, a polyurethane resin, a polybenzimidazole resin, andcopolymers and mixtures thereof.
 9. The underbody shield composition ofclaim 1, in which the thermoplastic core layer comprises polypropylene,glass fibers and microsphere lofting agents, and in which the film is apolypropylene homopolymer film.
 10. The underbody shield composition ofclaim 9, in which the film is directly disposed on the first surface ofthe core layer without any intervening layer or material.
 11. Theunderbody shield composition of claim 1, further comprising a scrimdisposed on a second surface of the core layer opposite the firstsurface of the core layer.
 12. The underbody shield composition of claim11, in which the scrim comprises glass fibers, aramid fibers, graphitefibers, carbon fibers, inorganic mineral fibers, metal fibers, metalizedsynthetic fibers, and metalized inorganic fibers.
 13. The underbodyshield composition of claim 11, further comprising an additional skinlayer disposed on the scrim.
 14. The underbody shield composition ofclaim 11, in which the thermoplastic core layer comprises polypropylene,glass fibers and microsphere lofting agents, in which the film is apolypropylene homopolymer film and the scrim is polyester nonwovenscrim.
 15. The underbody shield composition of claim 14, in which thefilm is directly disposed on the first surface of the core layer withoutany intervening layer or material and the scrim is directly disposed onthe second surface of the core layer without any intervening layer ormaterial.
 16. The underbody shield composition of claim 11, in which thescrim is disposed as one or more strips on the second surface of thecore layer.
 17. The underbody shield composition of claim 1, furthercomprising an additional core layer coupled to the core layer, theadditional core layer comprising a web of open celled structures definedby random crossing over of reinforcing fibers held together by athermoplastic polymer.
 18. The underbody shield composition of claim 17,in which the additional core layer further comprises a lofting agenteffective to increase a thickness of the additional core layer.
 19. Theunderbody shield composition of claim 17, in which the additional corelayer comprises a lower weight percentage of thermoplastic material thanan amount of thermoplastic material present in the core layer.
 20. Theunderbody shield composition of claim 1, in which the film is configuredto withstand more impacts as a thickness of the core layer is decreased.21-110. (canceled)